Effects of cyclodextrins on the flavor of goat milk and its yogurt.

UNLABELLED: Goat milk fat includes several branched chain fatty acids (BCFAs), like 4-methyloctanoic acid, which when free, are responsible for goaty flavor. This flavor limits the market opportunities for goat milk. Prior research showed that cyclodextrins (CDs) can reduce goaty flavor, presumably by binding free fatty acids. This research extends that observation. In odor ranking trials in citrate buffer at pH 4.8, ß-CD concentrations between 0% and 0.35% were increasingly effective in reducing odor intensity due to 4-methyloctanoic acid, but only when present in high molar excess. α-CD was also effective, but γ-CD was not. In lipase-treated goat milk only ß-CD was effective but at much lower molar excess, a difference potentially explained by several factors. One was that BCFAs bind to CDs in marked preference to their straight chain isomers. Displacement experiments with phenolphthalein disproved that hypothesis. The ability of ß-CD to reduce goaty flavor intensity extended to yogurt. An analytical panel showed that flavor of goat yogurt was reduced by addition of ß-CD, but only if added before heating and fermentation. A hedonic trial showed that consumers preferred unsweetened and sweet/vanilla-flavored goat yogurt more when ß-CD was included, P = 0.004 and 0.016, respectively. Males liked all yogurts more than females (P < 0.01), but there was a treatment × gender interaction (P = 0.016) for sweet/vanilla yogurt: sweet/vanilla masked the goaty flavor for males but not females. This results parallels previously demonstrated gender effects for sheepmeat flavor caused by BCFAs. PRACTICAL APPLICATION: ß-Cyclodextrin masks goaty flavor in yogurt, and with its GRAS status means it could be used in commercial goat yogurts and similar products so the real or perceived nutritional advantages of goat milk are not lost to goaty flavor.

Hybrid natural-synthetic chitosan resin: thermal and mechanical behavior.

Poly(methyl methacrylate) (PMMA) is one of the most commonly plastics used as dental-base material, due to its good biological compatibility and mechanical properties. Chitosan has wide application in chemical, biochemical and biomedical fields of research. In this work, chitosan (CTS) was functionalized with glycidyl methacrylate (GMA), to ease a further reaction with MMA. The resulting co-polymer was finally blended with PMMA and poly(butyl acrylate) PBA which works as a damper, the polymers were cured by UV to obtain the final resin. Characterization of UV-cured resins was carried out by thermal measurements, X-ray diffraction, atomic force microscopy (AFM), micro and nanoindentation, water absorption and elution in water. As a result a higher thermal stability of the final resin compared with the precursor co-polymer ((CTS-GMA)-g-PMMA) was obtained. The resin presented roughness in the nanometer scale and nanoparticles embedded in the acrylic matrix producing a tough material. However, XRD measurements show that all materials are in an amorphous state. Values of hardness and elastic modulus results were very near to those of the dentine. The results of elution in water of the tested resin samples show them as clinically acceptable as a dental base material.

Production of griseofulvin nanoparticles using supercritical CO(2) antisolvent with enhanced mass transfer.

Griseofulvin (GF) is a poor water soluble, antifungal agent. The bioavailability of the drug and its absorption from the gastrointestinal tract can be greatly improved by particle size reduction. In this work, supercritical antisolvent precipitation with enhanced mass transfer (SAS-EM) has been proposed for the production of GF nanoparticles. SAS-EM is a modification of the currently existing supercritical antisolvent (SAS) precipitation technique and also utilizes supercritical CO(2) as the antisolvent. In SAS-EM however, the solution jet is deflected by a surface vibrating at an ultrasonic frequency that atomizes the jet into small micro droplets. Further, the ultrasound field generated by the vibrating surface inside the supercritical media enhances mass transfer and prevents agglomeration due to increased mixing. GF nanoparticles of different sizes and morphologies have been obtained by varying the vibration intensity of the deflecting surface, which in turn is adjusted by changing the power supply to the attached ultrasound transducer. GF nanoparticles as low as 130 nm in size have been obtained corresponding to a power supply of 180 W. The effect of using different solvents on the size and morphology of the particles has also been studied.

Oral sustained-release bioadhesive tablet formulation of didanosine.

The objective of this study was to formulate a hydrogel-forming bioadhesive drug delivery system for oral administration of didanosine (ddI). The aim of this tablet dosage form is to improve the oral absorption of ddI by delivering it in small doses over an extended period and localizing it in the intestine by bioadhesion. Compressed tablets of ddI using Polyox WSRN-303, Carbopol 974P-NF, and Methocel K4M as the bioadhesive release rate-controlling polymers were prepared. The effect of polymer concentration on the release profile and in vitro bioadhesion of the matrix tablets was studied. Tablet formulations with Polyox WSRN-303 (10%) and Methocel K4M (30%) showed 93 and 90% drug release, respectively, after 12 h. The drug release was found to be linear when fitted in the Higuchi equation (square-root time equation), suggesting zero-order release. Carbopol 974-P-NF was found to inhibit the complete release of ddI because of drug-polymer interaction; hence, is not suitable for formulation of ddI. Drug diffusion and swelling of the polymer (anomalous Fickian release) was found dominant in ddI release. In general, in vitro bioadhesion increased with an increase in polymer concentration. Tablets containing a single polymer can be designed to form hydrogels serving the dual purpose of bioadhesion and sustained release.

Formulation, characterization, and in vitro release of glyburide from proliposomal beads.

The objective of our study was to formulate and evaluate proliposomes in the form of enteric-coated beads using glyburide as a model drug. The beads were enteric coated with Eudragit L-100 by a fluidized bed coating process using triethyl citrate as plasticizer. Content uniformity of glyburide was estimated using HPLC analysis of beads dissolved in methanol. These proliposomal beads formed liposomes on disintegration in phosphate buffered saline (pH 7.4), which was confirmed by transmission electron microscopy. The dissolution study of enteric-coated beads exhibited enhanced dissolution compared with pure drug and a marketed product. Liposomes can be successfully prepared for oral administration in the form of enteric-coated beads that may offer a stable system to produce liposomes for oral administration.

Edema, oncotic pressure, and free entropy: novel considerations for the treatment of edema through attention to thermodynamics.

Over 170 years after Richard Bright and a century after Ernest H. Starling, the development, location, and severity of edema in patients with renal impairment continue to baffle the predictions of most nephrologists. While much of the phenomenon can be explained by levels of serum proteins, or hydrostatic pressures, there are stunning exceptions well known to any practicing nephrologist. Some of the derangement is undoubtedly due to unmeasured but well-known variables, such as membrane permeability; however, other factors such as free entropy of plasma are also clearly involved. The study of other polyelectrolyte colloids, similar to plasma proteins, for industrial purposes has led to the identification of various phenomena such as counterion condensation that can result in loss of entropy and consequently osmotic pressure. Variables known to result in a loss of free entropy, such as pH, oxidation products and ligand binding, are discussed. Older equations developed by van't Hoff and Donnan might require replacement by newer mathematical models such as the nonlinear Poisson-Boltzmann equation or the Monte Carlo simulator. Attempts to restore free entropy to plasma would be a more physiological treatment of edema than diuretic use. Implications are noted for future drug development to treat edema.

The stability of amphotericin B in a mixture of fungizone and optimoist.

The physical and chemical stability of amphotericin B in a mixture of Fungizone and Optimoist was studied. The mixture was prepared by mixing equal volumes of Fungizone and Optimoist. The rate of sedimentation of amphotericin B was evaluated in Fungizone, Fungizone:Optimoist (1:1) and Fungizone:distilled water (1:1) mixture. The chemical stability of amphotericin B in a mixture of Fungizone:Optimoist (1:1) was determined by high-performance liquid chromatography from samples stored at different temperatures. The rate of sedimentation was faster when Fungizone was mixed with distilled water as compared to Optimoist. Amphotericin B was stable for three weeks stored in the refrigerator (4 deg C) and for three weeks at room temperature (25 deg C). Fungizone can be diluted with Optimoist for topical application. The mixture should be shaken well before administration in order to disperse any sediment.

Sonochemical reactions at 640 kHz using an efficient reactor. Oxidation of potassium iodide.

Ultrasound can be used to oxidize aqueous pollutants. However, due to economic reasons higher oxidation/destruction rates and higher energy efficiency are needed. Recent studies suggest that the higher ultrasound frequencies provide better oxidation rates than the conventional 20 kHz. Another area for improvement is reactor configuration. We have tested two new reactor configurations with proper focusing and reflection of ultrasound for maximum utilization. Reactor configuration plays an important role in the overall efficiency. In the new reactors, transducers and reaction mixture are separated by a polymer acoustic window which allows efficient transfer of ultrasound energy and not the heat from the transducer to the reaction mixture. One reactor at 640 kHz provides a 100% enhancement over the best reported rate for the oxidation of potassium iodide, on a per-Watt basis. Experiments conducted at varying initial KI concentrations show interesting behavior. Increasing the KI concentration by over eight fold merely increases the iodine production rate by two fold. This suggests that in the oxidation region surrounding the bubble, the KI concentration is much different than in the bulk. It is proposed that the hydrophobic bubble region has lower and near saturation KI concentration.

A rapid antibody-based test for Sec-2, a marker for the short arm of chromosome 2 of rye (2RS).

A simple monoclonal antibody-based screening test has been developed for the presence of translocations of the short arm of chromosome 2 of rye (2RS) with wheat chromosome 2B. 2RS encodes a set of about three polypeptides known as Mr 75 000 gamma-secalins. Use of the antibody test for these secalins enabled screening of several hundred seeds per day. The antibody could readily distinguish 2BL-2RS translocations and 2R substitutions from 1BL-1RS translocations or nontranslocation wheats. Use of the antibody in analysis of segregating progeny for Sec-2 in several wheat backgrounds was successful. Results with a selection of the seed population were checked using protein gel electrophoresis, with 100% correct confirmation. Key words : rye, wheat, seed proteins, translocation, diagnostic test.

Recovery of proteins and amino acids from reverse micelles by dehydration with molecular sieves.

A new method is presented to precipitate proteins and amino acids from reverse micelles by dehydrating the micelles with molecular sieves. Nearly complete precipitation is demonstrated for alpha-chymotrypsin, cytochromec, and trytophan from 2-ethylhexyl sodium sulfosuccinate (AOT)/isooctane/water reverse micelle solutions. The products precipitate as a solid powder, which is relatively free of surfactant. The method does not require any manipulation of pH, ionic strength, temperature, pressure, or solvent composition, and is applicable over a broad range of these properties. This general approach is compared with other techniques. This general approach is compared with other techniques for the recovery of biomolecules from reverse micelles. (c) 1994 John Wiley & Sons, Inc.

Our obsession with high resolution in gel electrophoresis: does it necessarily give the right answer?

Poor resolution of protein zones in an electrophoretic pattern may not necessarily be the result of poor technique. The example is given of the 'streak material', extracted from wheat flour, now recognised to be aggregated subunits of glutenin. The size distribution of the aggregated glutenin 'streak' is the key to elucidating the functional properties of wheaten dough. A stepped-layer gel technique has been devised to quantitate the proportions of aggregated glutenin in specific size groupings.

An IVS-I-117 (G-->A) acceptor splice site mutation in the alpha 1-globin gene is a nondeletional alpha-thalassaemia-2 determinant in an Indian population.

In 1991 we reported the identification of two deletional alpha-thalassaemia-2 determinants (-3.7 kb and -4.2 kb) and one nondeletional alpha-thalassaemia-2 determinant (Hb Koya Dora alpha 2 codon 142, TAA-->TCA) in a tribal population in Central India (Gupta et al, 1991). Evidence was obtained at that time for the possible presence of an additional nondeletional alpha-thalassaemia-2 because of low levels of Hb S (< 28%) in some Hb S heterozygotes with a simple alpha-thalassaemia-2 heterozygosity (-alpha/alpha alpha). This abnormality has now been identified as a G-->A mutation at IVS-I-117 of the alpha 1-globin gene (acceptor splice site) which makes this gene nonfunctional. Its frequency was established at approximately 6% which raises the total frequency of alpha-thalassaemia determinants in this population to approximately 60%. Subjects with a deletional alpha-thalassaemia-2 and the newly discovered alpha 1 acceptor splice junction mutation in trans appear to have an alpha chain deficiency similar to that of an alpha-thalassaemia-2 homozygote (-alpha/-alpha). An additional change (C-->G) at the Cap -4 site was observed in six alpha 1- and one alpha 2-globin genes; this polymorphism is not associated with a decrease in alpha chain synthesis and is not linked to the IVS-I-117 (G-->A) mutation.

Prevalence of initial drug resistance in tuberculosis patients attending a chest hospital.

Sputum samples from pulmonary tuberculosis patients attending a hospital for chest diseases and tuberculosis at Jaipur, India were directly subjected to sensitivity tests to detect drug resistance to streptomycin (S), isoniazid (I), rifampicin (R) and ethambutol (Emb) by slide culture technique. Drug resistance was observed to one or more drug in 19.9 per cent of the patients. I resistant organisms were present in 10.1 per cent of patients, S resistance in 7.6 per cent, R resistance in 3.0 per cent and Emb resistance in 2.6 per cent. Resistance was limited to a single drug in 16.7 per cent patients. Drug resistance was unrelated to age and sex of the patients.

Production of multiple wheat-rye 1RS translocation stocks and genetic analysis of LMW subunits of glutenin and gliadins in wheats using these stocks.

A triple (1AL.1RS/1BL.1RS/1DL.1RS) and three double (1AL.1RS/1BL.1RS, 1AL.1RS/1DL.1RS, 1BL.1RS/1DL.1RS) wheat-rye 1RS translocation stocks were isolated from a segregating population using the Gli-1, Tri-1 and Sec-1 seed proteins as genetic markers. These stocks carried 42 chromosomes and formed the expected multivalents (frequency of 14-25%) at metaphase 1. They gave floret fertility ranging from 40-60%. These stocks were subsequently used to determine the genetic control of low-molecular-weight (LMW) glutenin subunits in 'Chinese Spring' and 'Gabo' by means of two-step one-dimensional SDS-PAGE. All of the B subunits and most of the C subunits of glutenin were shown to be controlled by genes on the short arms of group-1 chromosomes in these wheats. The other C subunits were not controlled by group-1 chromosomes. The triple translocation line served as a suitable third parent in producing test-cross seeds for studying the inheritance of the LMW glutenin subunits and gliadins in wheat cultivars, e.g. 'Chinese Spring' and 'Orca'. The segregation patterns of the LMW glutenin subunits in these cultivars revealed that the subunits were inherited in clusters and that their controlling genes (Glu-3) were tightly linked with those controlling gliadins (Gli-1). The LMW glutenin patterns d, d and e in 'Orca' segregated as alternatives to the patterns a, a and a in 'Chinese Spring' controlled by Glu-A3, Glu-B3 and Glu-D3 loci on chromosome arms 1AS, 1BS and 1DS, respectively, thus indicating that these patterns were controlled by allelic genes at these loci.

Clinical, hematological, and molecular features in Sicilians with Hb S-beta-thalassemia.

The clinical, hematological, and molecular features of 81 patients with Hb S-beta-thalassemia and relatives from 76 unrelated families are reported. We analyzed the beta-thalassemia mutations and the beta S haplotypes in all patients and detected 6 different beta-thalassemia alleles: codon 39 (C-->T) (39 cases), IVS-I-1 (G-->A) (12 cases), IVS-II-1 (G-->A) (4 cases), IVS-I-6 (T-->C) (6 cases), IVS-I-110 (G-->A) (14 cases), and IVS-II-745 (G-->C) (6 cases). Eighty patients had haplotype #19 or the Benin type and one had haplotype #17 or the Cameroon type. The type of beta-thalassemia allele had the greatest influence on the phenotypic expression; this was observed for patients with Hb S-beta-thalassemia and for simple beta-thalassemia heterozygotes. The mild IVS-I-6 (T-->C) mutation produced borderline abnormal erythrocytic indices and Hb A2 levels in heterozygotes. Overall, there was a milder expression in beta(S) beta(+) patients (only 7.7% presented severe disease) than in those with the beta(S)beta(0) condition (22.6% had the severe form of the disease).

Hemoglobinopathies among the Gond tribal groups of central India; interaction of alpha- and beta-thalassemia with beta chain variants.

We have investigated the frequencies and types of alpha-thal, beta-thal, and Hb variants among nearly 200 inhabitants of villages in the Mandla and Jabalpur districts of Madhya Pradesh in Central India. Over 85% were tribals of the Gond group. alpha-Thal, as -alpha 3.7/and -alpha 4.2/, and the nondeletional Koya Dora mutation were present at the combined frequency of 0.54. There were indications for the presence of other nondeletional types of alpha-thal. alpha-Globin gene triplications were not observed. Four of the six beta-thal alleles observed were in the tribal groups; two (G----C at codon 30 and G----A at IVS-I-1) were found for the first time. The simultaneous presence of an alpha-thal (-alpha/alpha alpha or -alpha/-alpha) greatly improved the clinical and hematological condition of the patients with Hb S-beta(+)-thal (IVS-I-5; G----C). The lower frequency of alpha-thal among the beta-thal heterozygotes (f = 0.32) may indicate that some of the beta-thal alleles in the tribal populations originated from an outside source. Forty-one subjects had SS; all but one had beta S with haplotype #31, while one chromosome had haplotype #17. The presence of an alpha-thal-2 (f = 0.53) in the SS patients did not affect hematological data. The Hb F levels varied between 7.5% and 42.5% with high G gamma values. No difference in Hb F level between males and females was observed. Lower Hb F levels were present in 10 SS patients with an alpha-thal-2 homozygosity (average 16% versus 23.5% for eight SS patients with alpha alpha/alpha alpha) suggesting a decreased formation of alpha gamma dimers in severe alpha chain deficiency. Several younger SS patients (less than 10 years) also had high Hb F levels (32-42%). Variations in the sequence at -530 of the beta-globin gene; i.e. in the so-called silencer sequence, were present in all beta S chromosomes with haplotype #31, but were not considered important for understanding the variability in the Hb F level. gamma-Globin gene deletions (gamma-thal) and triplications were not observed.

Repeat open intracardiac operation--analysis of 55 patients.

Of the 4170 open intracardiac operations performed at our hospital in the last 6 years, 55 (1.3%) were reoperations. Of these failed valve repairs or valve substitutes formed the major group (58%) and the interval between first and second operation ranged from 6 months to 8 years. There were 4 deaths on table and another 6 patients died during their hospital stay giving an early mortality rate of 18 per cent. There was one late death during a follow-up period of 1 month to 3 years. There was no death due to perioperative bleeding complications. We conclude that it should now be possible to perform reoperations with an acceptable mortality and good late functional results.

Two-step one-dimensional SDS-PAGE analysis of LMW subunits of glutelin : 1. Variation and genetic control of the subunits in hexaploid wheats.

A collection of 222 hexaploid wheat cultivars (including the 207 cultivars studied by Gupta and Shepherd in 1988) from 32 countries was analyzed for variation in the banding patterns of LMW subunits of glutenin using a modified two-step 1-D SDS-PAGE. Seventy percent ethanol at high temperature (≥50 °C) was used to selectively dissolve the native glutenins containing A, B, and C subunits and not the albumins and globulins (non-prolamins). This procedure allowed the glutenin subunits A, B and C to be separated in a background free of albumins and globulins, which normally overlap the B and C subunits (LMW subunits of glutenin). Although 40 different B and C subunits were detected, except where the cultivars carried a 1BL-1RS translocation or 1B/1R substitution, each cultivar exhibited from 7 to 16 subunits. These subunits could be divided into 20 band patterns which fell into three groups on the basis of their mutual exclusiveness, with 6, 9, and 5 patterns. Analysis of substitution lines revealed that the different patterns in these groups are controlled by genes on chromosomes 1A, 1B, and 1D, respectively. The least number of subunits was controlled by chromosome 1A and approximately 40% of the cultivars did not contain any band controlled by this chromosome. Thirteen of the cultivars were found to consist of two biotypes with respect to LMW subunits of glutenin. The genetic, evolutionary, and technological implications of these findings are discussed.

Two-step one-dimensional SDS-PAGE analysis of LMW subunits of glutelin : 2. Genetic control of the subunits in species related to wheat.

Analysis of intergeneric substitution lines in hexaploid wheats by a two-step electrophoretic method of protein separation revealed that low-molecular-weight (LMW) subunits of glutelin in Triticum longissimum, T. Umbelullatum, Elytrigia elongata (2 x) were controlled by chromosomes/chromosome arms 1S (l) , 1U, and 1ES, respectively. A LMW glutelin band in Secale montanum was detected but its chromosomal location could not be determined. Genes controlling gliadins and HMW subunits of glutelin were also located on chromosome 1S (l) in T. longissimum.