Interaction kinetics of tetramethylrhodamine transferrin with human transferrin receptor studied by fluorescence correlation spectroscopy.

We applied fluorescence correlation spectroscopy (FCS) to characterize the interaction dynamics of fluorescence-labeled transferrin with transferrin receptor (hTfR) associates isolated from human placenta. The dissociation constant for the equilibrium binding of TMR-labeled ferri-transferrin to hTfR in detergent free solution was determined to be 7 +/- 3 nM. Binding curves were compatible with equal and independent binding sites present on the hTfR associates. Under pseudo-first-order conditions, with respect to transferrin, complex formation is monophasic. From these curves, association and dissociation rate constants for a reversible bimolecular binding reaction were determined, with (1.1 +/- 0.1) x 10(4) M-1 s-1 for the former and (6 +/- 4) x 10(-)4 s-1 for the latter. In dissociation exchange experiments, biphasic curves and concentration-independent reciprocal relaxation times were determined. From isothermal titration calorimetry experiments, we obtained an enthalpy change of -44.4 kJ/mol associated with the reaction. We thus conclude that the reaction is mainly enthalpy driven.     

The use of invertebrate functional groups to characterize ecosystem attributes in selected streams and rivers in south Brazil

An analysis conducted at nine stream/river sites in the Atlantic Forest region in the State of Paraná, Brazil used macroinvertebrate functional feeding group (FFG) assessments to evaluate ecological condition of the sites. The FFG approach categorizes qualitative macroinvertebrate collections according to their morphological-behavioral adaptations for food acquisition (e.g. scrapers that harvest non-filamentous, attached algae from stable surfaces in flowing water). FFG ratios were employed as surrogates for stream/river ecosystem attributes: balance between autotrophy and heterotrophy; linkage between riparian inputs of coarse particulate organic matter and in-stream food webs; relative dominance of fine particulate organic matter in transport (suspended load) compared to that deposited in the sediments; and geomorphic stability of the channel. The analyses indicated that all nine sites were heterotrophic, six of the nine carried expected levels of suspended organic load and showed below expected linkage with riparian inputs, and in only two were stable substrates limiting. The implications of the findings and recommendations for further analysis and modifications of the protocol are discussed.     

The challenge of choosing in cardiovascular risk management

Netherlands Heart Journal - Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. For many years guidelines have listed optimal preventive therapy. More...     

The Influence of Familial Predisposition to Cardiovascular Complications upon Childhood Obesity Treatment

Introduction

The aim was to investigate whether a familial predisposition to obesity related cardiovascular complications was associated with the degree of obesity at baseline and/or changes in the degree of obesity during a multidisciplinary childhood obesity treatment program.

Methods

The study included 1421 obese children (634 boys) with a median age of 11.5 years (range 3.1–17.9 years), enrolled in treatment for 0.04 to 5.90 years (median 1.3 years) at the Children''s Obesity Clinic, Denmark. At baseline, weight and height were measured, body mass index (BMI) standard deviation score (SDS) calculated, and self-reported information on familial predisposition to obesity, hypertension, type 2 diabetes mellitus (T2DM), thromboembolic events, and dyslipidaemia were obtained. A familial predisposition included events in biological parents, siblings, grandparents, uncles, and aunts. The treatment outcomes were categorically analysed according to the prevalence of familial predispositions.

Results

The median BMI SDS at enrolment was 3.2 in boys and 2.8 in girls. One-thousand-and-forty-one children had obesity in their family, 773 had hypertension, 551 had T2DM, 568 had thromboembolic events, and 583 had dyslipidaemia. Altogether, 733 had three or more predispositions. At baseline, familial T2DM was associated with a higher mean BMI SDS (p = 0.03), but no associations were found between the other predispositions and the children''s degree of obesity. During treatment, girls with familial obesity lost more weight, compared to girls without familial obesity (p = 0.04). No other familial predispositions were associated with changes in BMI SDS during treatment.

Conclusion

Obese children with a familial predisposition to T2DM showed a significantly higher degree of obesity at baseline and girls with familial obesity responded better to treatment. Besides these findings, no other associations were found between the occurrence of familial predispositions and the degree of obesity or changes herein during multidisciplinary childhood obesity treatment.     

Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>studies

Background  

Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.