Absorbability of Calcium From Common Beans

Absorption of calcium from white, red, and pinto beans, labeled with ⁴⁵Ca, was measured in 24 women in a three-way randomized design using a calcium load of 72 mg and milk as the referent. Fractional absorption for the three beans averaged 0.219 ± 0.047 and did not differ by type. Milk calcium absorption at the same load was more than two times higher, 0.451 ± 0.088 (P < 0.001). Oxalate content averaged 0.34%, and phytate averaged 1.7%, a stoichiometric excess relative to calcium. To evaluate the relation of phytate to reduced absorbability, labeled pinto beans were pre-treated with phytase and fed to 10 subjects. Fractional absorption rose, averaging 0.318 ± 0.071, (P <0.01 vs. untreated beans), but was significantly below that of milk. The difference was partly accounted for by phytate, with the remainder probably due to relatively high oxalate.     

Anti-allergic effect of low molecular weight β-glucan prepared by λ-irradiation

This study evaluated the anti-allergic effect of low molecular weight β-glucan (25 kDa) degraded by λ-irradiation. Allergy was induced in mouse models administrated with λ-irradiated low molecular weight and non-irradiated high molecular weight β-glucan, respectively, for 7 days. However, only the mice treated with low molecular weight β-glucan had a significantly decreased the total serum IgE and ovalbumin specific-IgE levels, and significantly increased Th 1 cytokine expression compared to only allergy induced mice. The allergic responses could be reduced by low molecular weight β-glucan treated λ-irradiation through the increased expression of Th 1 response and decreased expression of total IgE and antigen specific IgE.     

Effect of angiotensin I-converting enzyme (ACE) inhibitory peptide purified from enzymatic hydrolysates of <Emphasis Type="Italic">Styela plicata</Emphasis>

Angiotensin I-converting enzyme (ACE) inhibitory peptide was isolated from Styela plicata. The S. plicata was hydrolyzed with various proteases including Protamex, Kojizyme, Neutrase, Flavourzyme, Alcalase, trypsin, α-chymotrypsin, pepsin, and papain. The hydrolysate prepared with Protamex had the highest ACE inhibitory activity compared to the other hydrolysates. We attempted to isolate ACE inhibitory peptides from hydrolysate prepared with Protamex using ultra-filtration, gel filtration on a Sephadex G-25 column and reversed-phase high-performance liquid chromatography (RP-HPLC) on an ODS column. IC₅₀ value of the purified ACE inhibitory peptide was 24.7 μM, and Lineweaver–Burk plots suggest that the purified peptide from S. plicata acts as mixed-type inhibitor against ACE. Amino acid sequence of the purified peptide was identified as Met-Leu-Leu-Cys-Ser, with a molecular weight 566.4 Da. The results of this study suggest that peptides derived from S. plicata may be beneficial as anti-hypertension compounds in functional foods resource.     

Effect of angiotensin I converting enzyme inhibitory peptide purified from skate skin hydrolysate

Our objective was to evaluate the angiotensin I converting enzyme (ACE) inhibitory activity of skate skin protein hydrolysates and its corresponding fractions. The skate skin hydrolysates were obtained by enzymatic hydrolysis using alcalase, α-chymotrypsin, neutrase, pepsin, papain, and trypsin. Amongst the six hydrolysates, the α-chymotrypsin hydrolysate had the highest ACE inhibitory activity compared to other hydrolysates. The amino acid sequences of the purified peptides were identified to be Pro–Gly–Pro–Leu–Gly–Leu–Thr–Gly–Pro (975.38 Da), and Gln–Leu–Gly–Phe–Leu–Gly–Pro–Arg (874.45 Da). The purified peptides from skate skin had an IC₅₀ value of 95 μM and 148 μM, respectively, and the Lineweaver–Burk plots suggest that they act as a non-competitive inhibitor against ACE. Our study suggested that novel ACE inhibitory peptides derived from skate skin protein may be beneficial as anti-hypertension compounds in functional foods.     

Characterization of an antioxidant polylactic acid (PLA) film prepared with α-tocopherol,BHT and polyethylene glycol using film cast extruder

Polylactic acid (PLA) films were prepared with α-tocopherol, buthylated hydroxytoluene (BHT), and polyethylene glycol 400 (PEG 400) using a cast film extruder in an effort to create an antioxidant film. Film properties were characterized by radical scavenging activity and thermal, physical, and gas barrier properties. Final resin compounding and pelletization was achieved by a twin screw extruder and a pelletizator to permit the homogenization of all resin components prior to film casting. Three different PLA films were fabricated for this study: pure PLA film, PLA film with BHT and PEG 400 (BP-PLA film), PLA film with α-tocopherol, BHT, and PEG 400 (ABP-PLA film). The addition of PEG 400 into the pure PLA film decreased the glass transition temperature (T_g) of the film. The BP-PLA and ABP-PLA film had around 51 °C of T_g while pure PLA film had 66 °C. Due to the decreased T_g of both the BP-PLA and ABP-PLA film, both films had an increased elongation at break (%E). The addition of plasticizer into the pure PLA film also caused increased water vapor permeability (WVP) and decreased oxygen permeability (OP). The ABP-PLA film had highest DPPH radical scavenging activity, 90%, while pure PLA and BP-PLA film had only 0 and 14%, respectively.     

Development of the zone method for inhomogeneous non-isothermal participating plane layer media

The purpose of this paper is to present the first step in developing the zone method for inhomogeneous media that has never been published in the literature. It was derived and formulated using matrix relations for a plane layer system enclosing a non-isothermal and inhomogeneous gray and absorbing, emitting and isotropically scattering media. The media are enclosed by two infinite parallel plates that are opaque, diffuse, and gray, but the formulations allow transparent plate. The formulations recover homogeneous cases and satisfy the conservation relations. The accuracy of the zone method is verified by comparing with available exact solutions. Through the accuracy check, validity of the zone method is also shown. Thus, formulations presented can be used to test the accuracy of the works by others for the problem in the study that has many applications in engineering and science.

     

Swelling of thermosensitive interpenetrating polymer networks composed of poly(vinyl alcohol) and poly(acrylic acid)

The swelling behavior of interpenetrating polymer networks (IPNs) composed of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) in water was studied. The PVA/PAA IPN gels were prepared by four synthetic methods. The swelling behaviors of these IPNs made by different methods were compared. The differences in swelling behaviors of samples are discussed on the basis of their structural and physical differences. © 1996 John Wiley & Sons, Inc.     

Luteinizing hormone releasing hormone (LHRH) neurons maintained in nasal explants decrease LHRH messenger ribonucleic acid levels after activation of GABA(A) receptors

Inhibition of the LHRH system appears to play an important role in preventing precocious activation of the hypothalamic-pituitary-gonadal axis. Evidence points to gamma-aminobutyric acid (GABA) as the major negative regulator of postnatal LHRH neuronal activity. Changes in LHRH messenger RNA (mRNA) levels after alterations of GABAergic activity have been reported in vivo. However, the extent to which GABA acts directly on LHRH neurons to effect LHRH mRNA levels has been difficult to ascertain. The present work evaluates the effect of GABAergic activity, via GABA(A) receptors, on LHRH neuropeptide gene expression in LHRH neurons maintained in olfactory explants generated from E11.5 mouse embryos. These explants maintain large numbers of primary LHRH neurons that migrate from bilateral olfactory pits in a directed manner. Using in situ hybridization histochemistry and single cell analysis, we report dramatic alterations in LHRH mRNA levels. Inhibition of spontaneous synaptic activity by GABA(A) antagonists, bicuculline (10(-5) M) or picrotoxin (10(-4) M), or of electrical activity by tetrodotoxin (TTX, 10(-6) M) significantly increased LHRH mRNA levels. In contrast, LHRH mRNA levels decreased in explants cultured with the GABA(A) receptor agonist, muscimol (10(-4) M), or KCl (50 mM). The observed responses suggest that LHRH neurons possess functional pathways linking GABA(A) receptors to repression of neuropeptide gene expression and indicate that gene expression in embryonic LHRH neurons, outside the CNS, is highly responsive to alterations in neuronal activity.