Toxic Relationships and Arms-Race Coevolution Revisited.

Toxin evolution in animals is one of the most fascinating and complex subjects of scientific inquiry today. Gaining an understanding of toxins poses a multifaceted challenge given the diverse modes of acquisition, evolutionary adaptations, and abiotic components that affect toxin phenotypes. Here, we highlight some of the main genetic and ecological factors that influence toxin evolution and discuss the role of antagonistic interactions and coevolutionary dynamics in shaping the direction and extent of toxicity and resistance in animals. We focus on toxic Pacific newts (family Salamandridae, genus Taricha) as a system to investigate and better evaluate the widely distributed toxin they possess, tetrodotoxin (TTX), and the hypothesized model of arms-race coevolution with snake predators that is used to explain phenotypic patterns of newt toxicity. Finally, we propose an alternative coevolutionary model that incorporates TTX-producing bacteria and draws from an elicitor-receptor concept to explain TTX evolution and ecology.

[Medical image enhancement: Sharpening].

Most digital imaging systems provide opportunities for image enhancement operations. These are applied to improve the original image and to make the image more appealing visually. One possible means of enhancing digital radiographic image is sharpening. The purpose of sharpening filters is to improve image quality by removing noise or edge enhancement. Sharpening filters may make the radiographic images subjectively more appealing. But during this process, important radiographic features may disappear while artifacts that simulate pathological process might be generated. Therefore, it is of utmost importance for dentists to be familiar with and aware of the use of image enhancement operations, provided by medical digital imaging programs.

[Pseudo-color filter in two-dimensional imaging in dentistry].

Most digital systems that are currently used in two-dimensional imaging in dentistry provide opportunities for different image processing filters. One possible means of enhancing digital radiographic image is pseudocoloring (i.e., color conversion of gray-scale images). Recently, this method has become widely used in digital radiology. The human eye is more sensitive to differences in color than to differences in shades of gray. Theoretically, converting a gray scale intensity level of a digital image into colors could enhance the radiographic information. There have been some studies that applied pseudocoloring of digital radiographic images for the detection of caries and periodontal defects. However, thus far, this method failed to show a significantly improved ability for the detection of these lesions. Further investigations are necessary in order to develop specific algorithms that will increase the validity of pseudocoloring in two-dimensional imaging in dentistry.

[Elevated level of methylated catecholamine derivatives is a pathognomic laboratory sign of pheochromocytoma].

The levels of the methylated catecholamine derivatives (MCD) metanephrine and normetanephrine were measured in 46 patients operated on. The patients were divided into 2 groups: 1) 24 patients in whom chromaffinoma was histologically detected; their age varied from 9 to 75 years (mean 37.8 years); 2) 22 patients who had undergone adrenal cortical tumors or retroperitoneal tumors of extraadrenal genesis; their age ranged from 11 to 67 years (mean 44.3 years). In this group of patients, a histological study revealed aldosteromas in 7 cases, hormonally inactive adrenal cortical adenomas in 6, adrenocortical carcinoma in 5, corticosteroma in 1, adrenal lymphosarcoma in 1, adrenolypoma in 1, and renal cancer in 1. In all the patients from Group 1, there was an increase of one MCD index for instance of less than 110% of the upper normal range. The average excess of MCD levels over the upper normal range is 456% for metanephrine and 574% for normetanephrine. No increase in the level of daily MCD excretion was found in 21 out of the 22 Group 2 patients with nonchromaffin adrenal and retroperitoneal tumors. In this group, 1 patient with histologically verified mixed-cell adenocarcinoma of the adrenal cortex was observed to have a daily metanephrlne excretion increase by 17% above the upper reference range. Thus, the sensitivity of the method was 100%; its specificity was 95.5%. The lower confidence diagnostic interval for the values of daily MCD excretion was 714 ng/day for metanephrlne and 1500 ng/day for normetanephrine. The procedure for determining free MCD in plasma has a high sensitivity and specificity and may be once used as a screening for the symptomatic nature of disease in patients with arterial hypertension.

Formation of N-substituted 2-iminothiolanes when amino groups in proteins and peptides are modified by 2-iminothiolane.

The reagent 2-iminothiolane (2-IT) is used to introduce thiol groups into proteins and peptides by reactions of their amino groups. In this study, we report that the thiol adduct initially formed by the reaction of an amine with 2-IT (a 4-mercaptobutyramidine) is unstable and decays by a first-order process to a nonthiol product (an N-substituted 2-iminothiolane) with the loss of ammonia. The thiol adducts derived from amines of low pKa values (approximately 8; e.g., alpha-amino groups in peptides) decay more rapidly than those derived from amines of high pKa values ( similar 9.5; e.g., benzylamine, ethanolamine, lysine residues in proteins), with half-lives at pH 8 ranging from 0.3 to 3 h at 23 degrees C, and from 1 to 44 h at 0 degrees C. In the case of reactions of peptides with 2-IT, the substituents at the alpha-carbon also influence the decay of the initial thiol adducts. The decay of the initial thiol adduct to an N-substituted 2-iminothiolane was confirmed for the reaction between benzylamine and 2-IT by the isolation of N-benzyl-2-iminothiolane and its characterization by elemental analysis and mass spectrometry. The decay of the initial 4-mercaptobutyramidine is prevented if the thiol group is capped, e. g., in the form of a disulfide group, or if the solution is acidified (pH 3 to 4). Immediate capping of the thiol is, therefore, recommended when using 2-IT in the formation of bioconjugates. For amines of high pKa, the N-substituted 2-iminothiolane product can be cleaved by hydroxylamine, resulting initially in a thiol which then decays to N-hydroxy-2-iminothiolane regenerating the original amine. For amines of low pKa, the N-substituted 2-iminothiolane product can be hydrolyzed at pH 5 to generate a stable thiol with an amide functionality (an N-substituted 4-mercaptobutyramide).

Catalysis of reduction of disulfide by selenol.

The reduction of a disulfide to thiols, using sodium borohydride or dithiothreitol as reductant, is catalyzed by selenol. The rates of reduction of oxidized glutathione and bis(2-hydroxyethyl) disulfide by sodium borohydride are accelerated using a catalytic amount of selenol (8 mol% of the disulfide), by factors of 10 and 12, respectively. A rapid and convenient assay for disulfide has been developed, which involves its reduction with sodium borohydride in the presence of a catalytic amount of selenol, followed by acid quench and measurement of the resulting thiol by Ellman's assay. The disulfide bonds in proteins are reduced rapidly using excess dithiothreitol (5 mM) and selenol (0.8 mM), which can be separated conveniently from the reduced protein by gel filtration. The rates of reduction of disulfide bonds in immunoglobulin and alpha-chymotrypsinogen A by dithiothreitol are enhanced by a factor of 90 in the presence of selenol. The rate-determining step is the reaction of selenolate anion with disulfide. Selenocystamine, a commercially available diselende, is used as the precursor of the catalyst; it is reduced to its selenol in situ.

Added dietary methionine in starter pig diets containing spray-dried blood products.

Two experiments were conducted to determine the dietary methionine requirement of weanling pigs fed diets containing spray-dried porcine plasma and(or) blood meal in a phase-feeding program. In Exp. 1, 216 crossbred pigs (21 +/- 2 d of age and 4.9 kg BW) were fed diets (1.6% lysine, .52% cystine) containing 10% spray-dried porcine plasma and 1.75% spray-dried blood meal from d 0 to 21 postweaning. Pigs were fed one of six dietary treatments ranging from .28 to .48% total dietary methionine (.225 to .425% apparent digestible methionine). From d 0 to 14 and d 0 to 21 postweaning, ADG, ADFI, and gain:feed ratio (G:F) increased (quadratic, P < .01) as dietary methionine increased. Inflection point analysis projected .42 and .41% total dietary methionine to maximize ADG and G:F from d 0 to 14 and d 0 to 21 postweaning, respectively. In Exp. 2,216 crossbred pigs (21 +/- 3 d of age and 5.6 kg BW) were used to determine the dietary methionine requirement from d 7 to 28 postweaning. All pigs were fed the same diet (1.6% lysine, .44% methionine, .52% cystine) from d 0 to 7 postweaning. From d 7 to 28, pigs were assigned to one of six dietary treatments (1.3% lysine, .46% cystine) containing 10% dried whey and 3% spray-dried blood meal. Total dietary methionine levels ranged from .27 to .42% (.249 to .399% apparent digestible methionine). From d 7 to 14 postweaning, increasing dietary methionine increased (quadratic, P < .05) ADG, ADFI, and G:F (.34 to .35% total methionine projected by inflection point analysis).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of spray-dried blood meal on growth performance of the early-weaned pig.

A total of 1,956 weanling pigs were used in five experiments to evaluate spray-dried blood meal (SDBM) in starter pig diets. In Exp. 1, 432 weanling pigs (initially 6.9 kg BW and 21 d of age) were used to evaluate different protein sources in the d 7 to 28 postweaning diet. Pigs were fed a control diet containing 5% select menhaden fish meal or diets with 3.88% spray-dried porcine plasma, 2.49% SDBM (porcine), 5.74% soy protein concentrate, 5.74% moist extruded soy protein concentrate, or L-lysine.HCl and DL-methionine replacing select menhaden fish meal on an ideal protein basis. Pigs fed diets containing the spray-dried blood products had higher (P < .06) mean ADG than pigs fed the other protein sources. In Exp. 2, 744 weanling pigs (initially 5.8 kg BW and 21 d of age) were used to determine the effects of 0, 1, 2, 3, 4, or 5% SDBM (bovine) in the d 7 to 28 postweaning diet. Pigs fed increasing SDBM had greater (quadratic, P < .01) ADG and improved gain:feed ratio (G/F). Inflection point analysis projected optimum ADG and G/F at 1.9% SDBM. In Exp. 3, 216 weanling pigs (initially 10.9 kg BW and 42 d of age) were used to determine the effects of 0, .5, 1, 1.5, 2, and 2.5% SDBM (bovine) in the d 21 to 42 postweaning diet. Pigs fed increasing SDBM had decreased (linear, P < .05) ADG and G/F. In Exp. 4 and 5, 144 and 180 weanling pigs (initially 5.3 and 6.2 kg BW and 24 and 21 d of age, respectively) were used to evaluate either 2.5% spray-dried porcine, spray-dried bovine, or flash-dried bovine blood meal (Exp. 4) or 2.5% spray-dried bovine or spray-dried avian blood meal (Exp. 5). Pigs fed diets containing the spray-dried blood meals had improved ADG and G/F (P < .01) compared with pigs fed flash-dried blood meal. However, no differences (P > .10) were observed among treatments when pigs were fed spray-dried blood meals from different species. We conclude that spray-dried bovine, porcine, and avian blood meal are effective protein sources in starter pig diets (d 7 to 28 postweaning). However, SDBM is not necessary in the diets of older pigs (d 21 to 42 postweaning) for maximum growth performance.

The effect of spray-dried porcine plasma on growth performance in the early-weaned pig.

A total of 904 weanling pigs were used to investigate the effects of 1) spray-dried porcine plasma (SDPP), 2) blends of SDPP and spray-dried blood meal (SDBM), and 3) added dietary methionine in a SDPP-based diet on starter pig performance. In Exp. 1, 534 weanling pigs (initially 6.4 kg and 21 +/- 2 d of age) were used to determine the effects of either 0, 2, 4, 6, 8, or 10% SDPP and lactose as a replacement for dried skim milk in the Phase I diet (d 0 to 14 postweaning). All pigs were fed the same diet from d 14 to 28 postweaning. Average daily gain from d 0 to 14 increased (linear, P < .01) with increasing SDPP. From d 14 to 28, ADG decreased (linear, P < .03) as level of SDPP fed during Phase I increased. However, for d 0 to 28, ADG was increased (linear, P < .01) with increasing SDPP in the Phase I diet. Feed intake increased with increasing SDPP from d 0 to 14 and d 0 to 28 (quadratic, P < .04 and P < .08, respectively); however, gain/feed (G/F) was not affected. In Exp 2, 298 weanling pigs (initially 5.5 kg and 19 +/- 2 d of age) were used to determine the effects of replacing SDPP with SDBM in the Phase I diet. Pigs were fed either a diet containing 10% SDPP or diets with SDBM replacing 25, 50, 75, or 100% of the lysine provided by the SDPP.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of pre- and postweaning exposure to soybean meal on growth performance and on the immune response in the early-weaned pig.

The effect of pre- and postweaning exposure to soybean meal on postweaning growth performance and immune response by the early-weaned pig was analyzed. In Exp. 1, treatments were assigned in a 2 x 2 x 2 factorial arrangement. Pigs were derived from gilts fed either a soybean meal- or a corn gluten meal-based diet during gestation and lactation. Six to eight pigs per litter were either stomach-infused with or without (placebo) soybean meal during d 5 to 9 after farrowing. At weaning, 240 pigs (initially 5.1 kg, 21 +/- 1 d) were randomly allotted to either a corn-soybean meal or a corn-dried skim milk-dried whey diet based on gilt and infusion treatments. Average daily gain, ADFI, and gain:feed ratio were decreased (P < .05) on d 0 to 14 postweaning for pigs fed a soybean meal diet compared with pigs fed a milk diet. Skin-fold thickness after intradermal injection of soy protein and casein extracts on d 6 and measured on d 7 postweaning was not affected (P > .10) by dietary treatment, but serum immunoglobulin G titers to soybean glycinin and beta-conglycinin were increased (P < .01). From d 14 to 35 postweaning, all pigs were fed a common (1.25% lysine) corn-soybean meal diet containing 10% dried whey. Average daily gain, ADFI, and gain:feed ratio were decreased (P < .05) from d 14 to 35 for pigs fed a milk diet on d 0 to 14 postweaning. Serum immunoglobulin G titers were higher (P < .01) on d 21 postweaning for pigs fed soybean meal for the entire nursery period. Cumulative ADG (d 0 to 35) and gain:feed ratio were decreased (P < .05) for pigs fed a milk diet from d 0 to 14 compared with pigs fed a soybean meal diet. In Exp. 2, 104 pigs (initially 5.3 kg, 21 +/- 1 d of age) were used to determine the effect of 0, 7.5, 15.0, and 22.5% soybean meal in a high-nutrient-dense starter pig diet. Differences were not detected (P > .10) in ADG, ADFI, and gain:feed ratio during d 0 to 14, but ADFI decreased (linear, P < .05) and gain:feed ratio increased (linear, P < .05) during d 14 to 35 and for the entire 35-d trial as the level of soybean meal increased.(ABSTRACT TRUNCATED AT 400 WORDS)

The effect of moist extrusion of soy products on growth performance and nutrient utilization in the early-weaned pig.

One hundred seventy pigs averaging 21 +/- 1 d of age (initially 5.4 and 5.8 kg, respectively) were used in each of two experiments to determine the effect that further heat processing by moist extrusion has on the nutritional value of soybean products fed to the early-weaned pig (d 0 to 14 postweaning). The experiments were designed as randomized complete blocks with treatments arranged as a 2 x 3 factorial and a positive control. Main effects of moist extrusion and soy products and the interaction effects were analyzed. Raw soy flakes, commercial soy protein concentrate, and an experimental soy protein concentrate were used in Exp. 1 and a toasted soy flour replaced experimental soy protein concentrate in Exp. 2. A diet (1.4% lysine) containing primarily milk protein served as a positive control in both experiments. An interaction (P < .06) between moist extrusion processing and protein source existed from d 0 to 14 and from d 0 to 35 for ADG and gain:feed ratio (Exp. 1 and 2). Pigs fed moist-extruded soy products had improved (P < .01) ADG and gain:feed compared with pigs fed nonextruded soy products; the largest improvement was observed in pigs fed extruded, raw soy flakes and toasted soy flour (d 0 to 14). Apparent DM and N digestibilities (d 14) were increased (P < .05) when moist extrusion was used. Blood urea nitrogen and serum immunoglobulin G titers decreased (P < .05) in pigs fed moist-extruded soy products compared with titers in pigs fed nonextruded products. In Experiment 3, 100 pigs were used (initially 5.9 kg and 21 d of age) to compare moist and dry extrusion processing of soybean meal. Average daily gain, ADFI, gain:feed ratio, and apparent DM and N digestibilities were maximized (P < .05) in pigs fed a milk diet from d 0 to 14 postweaning. Pigs fed extruded soybean meal (moist or dry) had intermediate (P < .05) ADG, ADFI, gain:feed ratio, and apparent DM and N digestibilities from d 0 to 14. Pigs fed moist-extruded soybean meal from d 0 to 28 had increased (P < .10) ADG compared with pigs fed dry-extruded soybean meal. These data suggest that moist extrusion of less-refined soy products (raw soy flakes, toasted soy flour, and soybean meal) can result in growth performance comparable to that achieved by feeding highly refined soy products (soy protein concentrate) to the early-weaned pig.

[The dynamics of the indices of reactivity of the body in patients with chronic bronchitis and bronchiectasis in the course of treatment]. / Dinamika pokazatelei reaktivnosti organizma u bol'nykh khronicheskim bronkhitom i bronkhoéktaticheskoi bolezn'iu v protsesse lecheniia.

Complex determination of lymphocyte functional activity and the condition of the organism's immunological values in patients with chronic bronchitis and bronchiectasis helps in obtaining additional objective information which makes it possible to appraise the severity of the course of the disease, correct the treatment and determine its efficacy in different stages of the disease, come to a decision in regard to operative intervention, and form a judgement on the fullness of recovery. These tests acquire additional diagnostic value in patients with mild clinical manifestations of the disease as well as in the absence of its laboratory signs. A direct dependence between the severity of the disease and the above named values was revealed.

[The immunological reactivity indices of patients with chronic nonspecific lung diseases]. / Nekotorye pokazateli immunologicheskoi reaktivnosti bol'nykh khronicheskimi nespetsificheskimi zabolevaniiami legkikh.

At height of the disease patients with chronic bronchitis showed a reduction of immunological indices of reactivity of the body. A direct dependence was established between the severity of the course of the disease and degree of reactivity reduction. Absence of complete normalization of indices of immunological reactivity at discharge from the clinic indicates incomplete control of the inflammatory process and short-term character of the remission. The reaction of lymphocyte blast transformation may be used for detection of both latent and clinically manifest staphylococcal infection. Increased sensitivity to staphylococcal allergen results in a reduction of the phagocytic activity of neutrophils in patients with chronic bronchitis.

[Isolation and ultrastructure of Yersinia spheroplasts and protoplasts]. / Poluchenie i ul'trastruktura sferoplastov i protoplastov u iersinii.

The conditions suitable for the cultivation of Yersinia and the inhibition of their cell-wall synthesis have been selected with the aim of obtaining spheroplasts and protoplasts of these microorganisms. Penicillin, streptomycin and lithium chloride have proved to be not very suitable for this purpose as they induce essential changes in the structure of the cytoplasmic membrane in altered Yersinia forms. The addition of 1% of glycine (for Y. pseudotuberculosis), 1-1.5% of methionine in combination with growth stimulators has made it possible to obtain Yersinia spheroplasts and protoplasts with the intact cytoplasmic membrane, thus permitting the isolation and purification of the cytoplasmic membrane fraction.