What does the measurement of whole-body fatty acid rate of appearance in plasma by using a fatty acid tracer really mean?

We evaluated the validity of using a single fatty acid tracer to assess total plasma long-chain free fatty acid (FFA) kinetics and the relationship between the rate of appearance (R(a)) of fatty acids in plasma and the fatty acid composition of adipose tissue triglyceride (TG). A mixture of [(13)C]-labeled myristate, palmitate, stearate, oleate, and linoleate was infused in healthy men during basal conditions and during conditions that stimulate (epinephrine infusion) and inhibit (insulin infusion) lipolysis of adipose tissue TGs. Calculated total FFA, R(a) based on palmitate, oleate, or linoleate tracers, was within 15% of the measured sum of the individual fatty acid R(a) under all conditions, whereas stearate and myristate tracers consistently underestimated and overestimated total FFA R(a), respectively. The fatty acid R(a) profile closely matched the fatty acid profile of subcutaneous adipose tissue TGs during epinephrine infusion, but not during basal conditions and insulin infusion. Our data support the common practice of using labeled palmitate or oleate as fatty acid tracers for assessing total plasma FFA kinetics and suggest that a source of lipids other than adipose tissue TG release fatty acids into the systemic circulation.     

Effect of lead on ALA-D activity,metallothionein levels,and lipid peroxidation in blood,kidney, and liver of the toadfish Halobatrachus didactylus

The effects of lead (Pb) on ALA-D activity, metallothionein (MT) levels, and lipid peroxidation in liver, kidney, and blood of the toadfish Halobatrachus didactylus were investigated. A time-course experiment was performed with sampling on days 0, 2, 5, and 7 following intraperitoneal Pb injection. This indicated a rank order for lead concentration of kidney > liver > blood in fish exposed to Pb. No significant variation of ALA-D activity was observed in liver and kidney while in blood, a slight decrease of ALA-D activity was found but this was not attributed to acute metal stress. Hepatic and renal MT levels were both affected in different ways by metal uptake. The progressive decrease of MDA concentration in the liver and the lack of a clear induction in kidney suggested the hypothesis that Pb is not a good inductor of lipid peroxidation. The histological and histochemical results demonstrated degenerative effects of lead accumulation on the tissues and the activation of lysosomal responses to induced stress.     

Fundamental tone estimates for elliptic operators in divergence form and geometric applications

We establish a method for giving lower bounds for the fundamental tone of elliptic operators in divergence form in terms of the divergence of vector fields. We then apply this method to the Lr operator associated to immersed hypersurfaces with locally bounded (r + 1)-th mean curvature Hr + 1 of the space forms Nn+ 1(c) of constant sectional curvature c. As a corollary we give lower bounds for the extrinsic radius of closed hypersurfaces of Nn+ 1(c) with Hr + 1 > 0 in terms of the r-th and (r + 1)-th mean curvatures. Finally we observe that bounds for the Laplace eigenvalues essentially bound the eigenvalues of a self-adjoint elliptic differential operator in divergence form. This allows us to show that Cheeger's constant gives a lower bounds for the first nonzero Lr-eigenvalue of a closed hypersurface of Nn+ 1(c).     

Serum fetuin-A levels link inflammation and cardiovascular calcification in hemodialysis patients

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of mortality in hemodialysis (HD). An elevated incidence of cardiovascular calcifications (CVC) is observed in HD. Fetuin-A is an important inhibitor of CVC. Reduced fetuin-A levels associate with inflammation and increased cardiovascular (CV) mortality in HD. In this study we investigated the association of fetuin-A levels and CVC. METHOD: We evaluated a cohort of 115 patients (67 males), aged 63 +/- 16 years with a HD vintage >or=9 months. Presence of CVC was assessed by ultrasound imaging of the abdominal aorta, common carotid arteries, bilateral ilio-femoral axis, aortic and mitral cardiac valves. The presence of CVC was analyzed as a CVC score (CVCS) (0-7) according to the number of CVC sites. Patients were arbitrary stratified in three groups: group I (CVCS = 0), group II (0 < CVCS < 6) and group III (CVCS >or= 6). Patients without CVC were younger, non-diabetic and with a negative history for CV events. RESULTS: Patients with evidence of CVC in more than 5 sites had lower serum fetuin-A levels (0.41 +/- 0.22 g/l) compared to patients with CVCS = 0 (0.51 +/- 0.17 g/l, p = 0.048). In addition a worse CVCS was associated with higher serum levels of C-reactive protein (p = 0.002) and fibrinogen (p < 0.001). Serum fetuin-A levels lower than 0.290 g/l were associated with higher risk of a worse CVCS, independently from traditional risk factors. CONCLUSION: Chronic inflammation in HD patients leads to lower serum fetuin-A levels. The present study confirms the independent and significant association between reduced serum fetuin-A levels and multi-site CVC in HD.     

Colorectal schistosomiasis

The role of colonoscopic polypectomy for schistosomal polyps was studied. The results showed that, in spite of the large number of polyps, a total of 404 polyps were removed from 20 patients. The procedure is feasible with minimal complications. A marked reduction of rectal bleeding occurred in half the patients, and the remaining half had minimal symptoms. Colonoscopic polypectomy gives equal results to colonic excision for schistosomal polyps.     

Photoperiodic control of the timing of testicular regression in white-throated sparrows

Photosensitive white-throated sparrows were transferred from a nonstimulatory LD 8:16 light cycle to either a stimulatory LD 13:11 or LD 20:4 light cycle on Day O. While some birds remained on these stimulatory photoperiods throughout the study, other birds were transferred from LD 13:11 to LD 20:4 on Day 50, or from LD 20:4 to LD 13:11 on Day 30 after the testes had reached a width of about 4.0 mm. The testes of birds continuously exposed to LD 13:11 grew more slowly, reached a larger maximum size, and spontaneously regressed later than the testes of birds continuously maintained on LD 20:4. Spontaneous testicular regression occurred at the same time (between Days 90 and 120) in sparrows that were transferred from LD 13:11 to LD 20:4 on Day 50 as in sparrows that were maintained continuously on LD 13:11. Following testicular growth in sparrows that were exposed initially to LD 20:4, the transfer to a presumably photostimulatory LD 13:11 cycle induced rapid testicular regression suggesting that LD 13:11 was no longer being interpreted as a long day. These results suggest that in nature, the timing of spontaneous testicular regression which occurs after a prolonged exposure to photostimulatory long days may be (1) programmed by the LD cycle the bird is exposed to during gonadal growth, and/or (2) due to a decrease in day length after the summer solstice even though the length of the day is still longer than that which previously initiated testicular growth.