Hollow Plasma Acceleration Driven by a Relativistic Reflected Hollow Laser

In order to address the present difficulty in experimentally generating the relativistic Laguerre-Gaussian laser, primarily due to damage caused to optical modulators, a high-reflectivity phase mirror is applied in the femtosecond petawatt laser system to generate a relativistic hollow laser at the highest intensity of 6.3×10^{19}  W/cm^{2} for the first time. A simple optical model is used to verify that the vortex laser may be generated in this new scheme; using such a relativistic vortex laser, the hollow plasma drill and acceleration are achieved experimentally and proven by particle-in-cell simulations. With the development of the petawatt laser, this scheme opens up possibilities for the convenient production of the relativistic hollow laser at high repetition and possible hollow plasma acceleration, which is important for a wide range of applications such as the generation of radiation sources with orbital angular momentum, fast ignition for inertial confinement fusion, and jet research in the astrophysical environment.

Collisionless Shock Acceleration of High-Flux Quasimonoenergetic Proton Beams Driven by Circularly Polarized Laser Pulses

We present experimental studies on ion acceleration using an 800-nm circularly polarized laser pulse with a peak intensity of 6.9×10^{19}  W/cm^{2} interacting with an overdense plasma that is produced by a laser prepulse ionizing an initially ultrathin plastic foil. The proton spectra exhibit spectral peaks at energies up to 9 MeV with energy spreads of 30% and fluxes as high as 3×10^{12}  protons/MeV/sr. Two-dimensional particle-in-cell simulations reveal that collisionless shocks are efficiently launched by circularly polarized lasers in exploded plasmas, resulting in the acceleration of quasimonoenergetic proton beams. Furthermore, this scheme predicts the generation of quasimonoenergetic proton beams with peak energies of approximately 150 MeV using current laser technology, representing a significant step toward applications such as proton therapy.

Electron Accumulation and Emergent Magnetism in LaMnO_{3}/SrTiO_{3} Heterostructures

Emergent phenomena at polar-nonpolar oxide interfaces have been studied intensely in pursuit of next-generation oxide electronics and spintronics. Here we report the disentanglement of critical thicknesses for electron reconstruction and the emergence of ferromagnetism in polar-mismatched LaMnO_{3}/SrTiO_{3} (001) heterostructures. Using a combination of element-specific x-ray absorption spectroscopy and dichroism, and first-principles calculations, interfacial electron accumulation, and ferromagnetism have been observed within the polar, antiferromagnetic insulator LaMnO_{3}. Our results show that the critical thickness for the onset of electron accumulation is as thin as 2 unit cells (UC), significantly thinner than the observed critical thickness for ferromagnetism of 5 UC. The absence of ferromagnetism below 5 UC is likely induced by electron overaccumulation. In turn, by controlling the doping of the LaMnO_{3}, we are able to neutralize the excessive electrons from the polar mismatch in ultrathin LaMnO_{3} films and thus enable ferromagnetism in films as thin as 3 UC, extending the limits of our ability to synthesize and tailor emergent phenomena at interfaces and demonstrating manipulation of the electronic and magnetic structures of materials at the shortest length scales.

In situ study of the annealing process of a polyethylene cast film with a row-nucleated crystalline structure by SAXS

The secondary crystallization has more effect on polyethylene crystal thickening than melt recrystallization during the annealing process.

Proposal of a new degradation mechanism of enalapril maleate and improvement of enalapril maleate stability in tablet formulation with different stabilizers

Enalapril maleate (EM) is unstable in poorly designed tablet formulations. To improve the stability of EM, the degradation mechanism should be elucidated. In this study, we found that several commonly used excipients promoted the degradants of EM, particularly a diketopiperazine derivative (DKP). We propose two degradation pathways in which both acid and alkali can promote the formation of DKP, although previous reports suggested that DKP is produced mainly in acidic media. Based on the degradation pathways, we believe that subtle control of the microenvironmental pH can inhibit the formation of DKP. This was confirmed by the observation that the degradation rate became slower when certain organic acids were added to the binary mixtures of EM and excipient. The data showed that the stability of EM in the ternary mixtures was much higher than that in binary mixtures. It was further proved that tablets containing these organic acids produced less DKP after the accelerated test. We also found that the formation of DKP in tablets varied with different ratios of tartaric acid, which was used as a model organic acid. This illustrated that an optimum ratio of tartaric acid is required. These results indicated that the stability of EM in tablet formulation is closely associated with microenvironmental pH and the addition of a suitable organic acid based on the reaction mechanism is an effective strategy for improving the stability of EM.

The prenatal porcine intestine has low transforming growth factor-beta ligand and receptor density and shows reduced trophic response to enteral diets

Transforming growth factor-beta (TGF-β) plays a role in enterocyte proliferation control, cell differentiation, and immune regulation via binding to specific TGF-β receptors (TGF-β R) in the intestinal epithelium. Endogenous TGF-β production is low in the intestine during the perinatal period, but some exogenous TGF-β ligands are supplied by amniotic fluid intake in the fetus and by colostrum ingestion in the neonate. It is not clear, however, whether luminal TGF-β receptors are present and functional at this critical time. We studied intestinal TGF-β receptors by immunohistochemistry during the last 20% of gestation in pigs and in chronically catheterized fetuses following exposure to colostrum, milk, and amniotic fluid (control). In fetal pigs, the TGF-β Rs were predominantly localized to the crypt epithelium, but staining intensity increased markedly just before term and shifted to the villous epithelium in newborn pigs, concurrently with marked increases in villous heights and crypt depths (+100–200%, P < 0.05). In contrast to previous observations in term newborn pigs, fetal pigs did not show any milk-induced change in TGF-β receptor densities or localization, although a moderate increase in villous height was observed, relative to control (+25–50%, P < 0.05). We conclude that intestinal TGF-β receptor density and localization are immature and unresponsive to TGF-β containing milk diets in prenatal pigs. Immaturity of TGF-β-mediated immune regulation may play a role in the increased sensitivity of preterm neonates to diet-induced intestinal inflammatory disorders.

Overexpression of cyclooxygenase-2 correlates with tumor angiogenesis in endometrial carcinoma

The inducible enzyme cyclooxygenase-2 (COX-2) is an important mediator of angiogenesis and tumor growth. Several reports have indicated that vascular endothelial growth factor (VEGF)-positive tumors are associated with an increased amount of COX-2 protein. This study evaluated the significance of COX-2 in 34 patients with endometrial carcinoma and its relationship to angiogenesis. Immunohistochemical expression of COX-2 and VEGF was analyzed on paraffin-embedded tissue sections. Microvessel density (MVD) of endometrial carcinoma was also determined with anti-CD(34) as the label. COX-2 messenger RNA (mRNA) was analyzed by reverse transcription-polymerase chain reaction. The expression rate of COX-2 in 34 cases was 64.7% but not in control endometrium. COX-2 mRNA was higher in tumor specimens than in normal tissues. The level of COX-2 expression was higher in grade 2 tumors than in grade 3 tumors (P < 0.05). MVD was higher in COX-2-positive and VEGF-positive cases than in COX-2-negative and VEGF-negative cases (P < 0.05). The expression of COX-2 was positively correlated with the expression of VEGF and MVD (P < 0.05 and P < 0.01, respectively). The present findings suggest that overexpression of COX-2 may induce the expression of VEGF, increase angiogenesis, and enhance tumor growth.

[Expression of thyrotropin-releasing hormone receptor mRNA in the rat testis development]

In order to investigate the regulation of thyrotrophin-releasing hormone receptor (TRH-R) expression in rat testis, and to study their function in spermatogenesis, oligonucleotide primers were designed from the sequences of rat pituitary TRH-R cDNA for reverse transcription-polymerase chain reaction (RT-PCR). Specific fragments of TRH-R cDNA were cloned. DNA sequence analysis indicated that cDNA sequence of TRH-R from rat testis was consistent with those of pituitary TRH-R cDNA. The non-radioactive in situ hybridization (NR-ISH) technique was applied to localize cells encoding TRH-R mRNA in the rat testis. Hybridization signals were detected exclusively in the leydig cells, but not in the spermatogenetic cells of the rat testis. TRH-R mRNA in the testis was quantitated in RNA samples prepared from rats at different developmental stages by real time quantitative RT-PCR. The quantitative analyses demonstrated that no TRH mRNA could be detected at the earliest stage (day 8). TRH mRNA signals were detected on day 15 and increased progressively on day 20, 35, 60 and 90. These results suggested that rat testis could specifically express TRH-R, and the transcription of TRH-R gene in the rat testis was development-dependent.

Near-infrared spectroscopic technique for detection of beef hamburger adulteration

A near-infrared spectroscopic technique was developed to detect beef hamburgers adulterated with 5-25% mutton, pork, skim milk powder, or wheat flour with an accuracy up to 92.7%. The accuracy of detection increased with the increase of adulteration level. When an adulterant was detected, the adulteration level was further predicted by calibration equations. The established calibration equations for predicting adulteration levels with mutton, pork, skim milk powder, and wheat flour had standard errors of cross-validation of 3.33, 2.99, 0.92, and 0.57% and coefficients of variance of 0.87, 0.89, 0.99, and 1.00, respectively. The results of this study indicate that near-infrared spectroscopy is potentially useful in detection of beef hamburger adulteration.

Gastrointestinal stability and absorption of insulin in suckling pigs

Stability and absorption of orally administered fluorescein-isothiocyanate labeled insulin (FITC-insulin) in the gastrointestinal (GI) tract were investigated in newborn and 3-day-old pigs. The uptake of FITC-insulin by the intestinal epithelial cells was visualized using confocal laser scanning microscopy. Following oral administration, 3 h later 56 and 88% of orally administered fluorescence was found in the GI tract in newborn and 3-day-old piglets, respectively. Chromatographic analysis revealed that 15-37% of fluorescence recovered from the gastric and proximal intestinal contents was eluted in the void volume of a Sephadex G-25 column. It was also observed that oral administration of FITC-insulin at a dose of 100 nmol/kg body weight led to a significant decrease in blood glucose in newborn pigs (P<0. 05) but not in 3-day-old pigs. Microscopic examination showed that FITC-insulin was taken up via the vesicular transport mechanism throughout the whole small intestine but the ileum appeared to be a preferred site for FITC-insulin transport in newborn pigs. In 3-day-old pigs, the uptake of FITC-insulin occurred only in the distal part of the small intestine. These findings suggest that milk-borne insulin may partially survive in the GI lumen and subsequently act on the gastrointestinal tract in suckling piglets, while GI absorption of milk-borne insulin is limited to newborn pigs.

Stability of insulin-like growth factor I in the gastrointestinal lumen in neonatal pigs

BACKGROUND

Insulin-like growth factor (IGF)-I is present in the milk of various species. A prerequisite for any biological activity of milk-borne IGF-I in the suckling young is to survive the gastrointestinal luminal digestion. In the present study, the stability of IGF-I was examined in the gastrointestinal lumen in neonatal pigs.

METHODS

Iodine-labeled IGF-I was incubated in the gastrointestinal luminal fluids of 3-day-old suckling and 45-day-old weaned pigs at 37 degrees C for 20 minutes. Degradation of the peptide was analyzed by trichloroacetic acid (TCA) precipitation, liquid chromatography, and receptor binding assay.

RESULTS

IGF-I remained unchanged in the gastric fluids of suckling and weaned pigs when determined by TCA precipitation. IGF-I degraded 3%, 18%, and 37% in the luminal fluids of the proximal, mid and distal small intestine in suckling piglets compared with 53%, 62%, and 54% in weaned pigs. The results were supported by the chromatography and receptor binding analysis. Porcine colostrum had a capacity to protect IGF-I from gastrointestinal luminal digestion in weaned pigs.

CONCLUSION

Milk-borne IGF-I is stable in the gastrointestinal lumen in suckling pigs and may play a role in regulating postnatal development in the suckling young.

Determination of chemical composition of commercial honey by near-infrared spectroscopy

The feasibility of using near-infrared spectroscopy to determine chemical composition of commercial honey was examined. The influences of various sample presentation methods and regression models on the performance of calibration equations were also studied. Transmittance spectra with 1 mm optical path length produced the best calibration for all constituents examined. The regression model of modified partial least squares (mPLS) was selected for the calibration of all honey constituents except moisture, for which the optimal calibration was developed with PLS. Validation of the established calibration equations with independent samples showed that the spectroscopic technique could accurately determine the contents of moisture, fructose, glucose, sucrose, and maltose with squared correlation coefficients (R(2)) of 1.0, 0.97, 0.91, 0.86, and 0.93 between the predicted values and the reference values. The prediction accuracy for free acid, lactone, and hydroxymethylfurfural (HMF) contents in honey was poor and unreliable. The study indicates that near-infrared spectroscopy can be used for rapid determination of major components in commercial honey.

Stability and distribution of orally administered epidermal growth factor in neonatal pigs

Stability and distribution of orally administered epidermal growth factor (EGF) were examined in newborn and 5-day-old pigs. Forty-five minutes after oral administration of iodine-125 labeled EGF, 60 and 50% of the radioactivity administered were recovered from the internal organs in newborn and 5-day-old pigs, respectively. In both age groups, over 95% of the recovered radioactivity was found in the gastrointestinal tract, of which 78-86% was found in the luminal contents with the remaining found in the gastrointestinal wall. Within the gastrointestinal tract, 65-71% of radioactivity was found in the stomach, 27-30% in the proximal and mid small intestine and 3-4% was found in the distal part of the small intestine. There were no significant differences in the overall distribution of orally administered radioactivity between two age groups. Based on liquid chromatography and trichloroacetic acid precipitation, a substantial amount of EGF recovered from the luminal contents (63-86%) and the gastrointestinal wall (42-81%) remained "intact". The receptor binding ability of the EGF recovered from the gastric contents was 96-102% comparable to the native EGF tracer. The receptor binding ability remained high (40-58%) in the proximal small intestinal lumen and it decreased to 15% in the distal small intestinal lumen in newborn pigs. In 5-day-old pigs, EGF recovered from the small intestinal contents had 5 to 24% receptor binding ability when compared with native EGF tracer. The receptor binding ability of the EGF recovered from all other organs was below 5% with an exception of the gastric wall, from which recovered EGF retained 9 to 26% receptor binding ability. These results indicate that most of orally ingested EGF remained in the gastrointestinal tract in neonatal pigs 45 min after oral ingestion, and significant amount of the ingested EGF remained biologically active. It suggests that milk-borne EGF can survive in the gastrointestinal tract and may play a role in regulating gut development in neonatal animals.

Comparison of growth and development of the exocrine pancreas in pigs and rats during the immediate postnatal period

This study compared pancreatic tissue growth and functional changes during the first 3 postnatal days in piglets and rat pups. In piglets the absolute weight and the relative weight per unit body weight of the pancreas increased by 97 and 70%, respectively, while in rat pups the same parameters decreased by 33 and 48%, respectively, during this period. The specific activity of pancreatic amylase rose by 336% while that of trypsin, chymotrypsin and lipase remained at newborn level in piglets. In rat pups the specific activities of all enzymes measured declined by 61 to 92% during the first 3 postnatal days. The rate of postnatal pancreatic growth in the two species coincide with the levels of epidermal growth factor and insulin-like growth factors in maternal milk as reported in the literature, suggesting that milk-borne growth factors may stimulate pancreatic development in newborn animals.

Capillary electrophoretic behavior of milk proteins in the presence of non-ionic surfactants

The electrophoretic behavior of alpha-lactalbumin and beta-lactoglobulins (A and B) in the presence of non-ionic surfactants was studied by capillary electrophoresis (CE), using a poly(ethylene glycol) coated capillary column. The surfactants (Tween 20, Brij 35 and 78) were used as buffer additives. The separation is based on the difference in the strength of protein-surfactant association complexes, which results in a change of the effective electrophoretic mobility. The modification of the electrophoretic mobilities of proteins was observed and this variation permitted the estimation of the interaction between protein and surfactant. The effect of surfactant type and concentration on the migration behavior of protein in CE is discussed. It is found that the retention behavior of the milk proteins (the alpha-lactalbumin and the beta-lactoglobulins) in CE is very different. The pH of the buffer and the surfactant type influence significantly the protein-surfactant interactions.

Agrobacterium-mediated transformation of élite indica and japonica rice cultivars

A rapid, efficient, routine system has been established for Agrobacterium tumefaciens-mediated production of hundreds of fertile transgenic plants from commercially important rice cultivars, including an indica cultivar, Pusa Basmati 1. Calli induced from embryos of mature rice seeds were cocultivated with A. tumefaciens strain LBA4404 carrying the plasmid pTOK233, then exposed to hygromycin selection followed by an efficient regeneration system. Based on the total number of calli co-cultivated, the transformation frequencies of independent transgenic rice plants including cultivars Pusa Basmati 1, E-yi 105, E-wan 5 and Zhong-shu-wan-geng, were 13.5, 13.0, 9.1, and 9.3%, respectively. T1 seeds were harvested within 7-8 mo of initiation of mature embryo cultures. Data from Southern hybridization analysis proved that foreign genes on T-DNA were stably integrated into the rice genome at low copy/site numbers. Mendelian inheritance of the transgenes was confirmed in T1 progeny.

Impact of Yersinia enterocolitica enteritis on disaccharidase activity and small intestinal morphology in colostrum-deprived newborn piglets

The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birth. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infection, or antibiotic therapy was commenced on day 5 and the animals killed on day 14 (n = 5). Compared with the non-infected controls, infected animals had reduced mucosal lactase and sucrase, but not maltase activity, while after antibiotic therapy, previously infected piglets had a lower lactase and a higher maltase and sucrase activity. Lactase activity was significantly reduced in the duodenum and jejunum, and mean values were lower in the ileum, but the difference did not reach significance; maltase activity was greater at all ages from the distal jejunum to the mid-ileum; sucrase activity was reduced in all segments up to day 5 but after antibiotic therapy was increased in the jejunum and appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. There was a reduced villus height:crypt depth ratio, crypt hyperplasia and increased crypt cell proliferation. Morphological maturation, indicated by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 14 days of age when only the ileum remained immature. In infected piglets, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected piglets appears to be due to physical damage to the mucosa resulting in faster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impair the ability to utilise dietary carbohydrate and may have long-term effects on growth and immunological responses of the gut.

Growth and development of the exocrine pancreas in newborn pigs: the effect of colostrum feeding

This study examined the growth and development of the pancreas in naturally suckled piglets during the first 3 postnatal days and the effects of colostrum feeding on the pancreatic development. The results showed that in naturally suckled piglets, the absolute weight of the pancreas increased 51% during the first day and 86% by the 3rd day, and the relative weight per unit body weight increased 37% during the first day and 47% by the 3rd day. Associated with the rapid weight gain was a significant increase in pancreatic DNA content and enlargement of pancreatic exocrine acinar units, the latter apparently resulted from an increase in number rather than size of acinar cells. It was further shown that the rapid pancreatic growth was related to colostrum ingestion as significant pancreatic weight gain was observed in piglets bottle-fed porcine colostrum or trypsinized porcine colostrum but not in piglets bottle-fed 5% lactose solution. Trypsinized porcine colostrum was apparently more potent than native porcine colostrum in stimulating pancreatic growth in newborn pigs. It is speculated that colostrum-borne growth factors and/or postnatal surge of gut hormones following onset of oral feeding are the major factors responsible for the rapid postnatal pancreatic growth in newborns.

Oral insulinlike growth factor-I stimulates intestinal enzyme maturation in newborn rats

Insulinlike growth factor-I (IGF-I) has been found in the milk of various species. To investigate if milk-borne IGF-I has any effect on postnatal gut development in neonatal animals, newborn rat pups were given orally 1 microg recombinant human IGF-I daily for 3 days. For comparison, a separate group of newborn pups was given 150 microg hydrocortisone, the hormone known to stimulate intestinal maturation in neonatal rats. Oral IGF-I treatment had no significant effect on the animal body weight nor on the weight of the stomach, small and large intestines, and pancreas. Oral administration of hydrocortisone significantly reduced body weight gain, but it had no apparent effect on internal organ weights. Both IGF-I and hydrocortisone treatments, however, significantly increased lactase, maltase and sucrase activities and hydrocortisone significantly increased aminopeptidase activity at the proximal small intestine when compared with the control. The finding supports the hypothesis that milk-borne IGF-I may play a role in regulating postnatal gut development in the suckling young.

Gastrointestinal absorption of insulinlike growth factor-I in neonatal pigs

To determine if milk-borne insulinlike growth factor-I (IGF-I) is absorbed in neonatal piglets, recombinant human IGF-I was iodinated and then administered via an oral-gastric tube to newborn and 3-day-old piglets together with fluorescent isothiocyanate dextran (FITC-D70s, a macromolecular marker for assessment of gut closure). Results showed that total radioactivity and trichloroacetic acid (TCA)-precipitable radioactivity rose significantly in the plasma of both newborn and 3-day-old piglets 1 hour after oral-gastric administration of 125I-IGF-I, although the magnitude of increase was greater in newborns than in 3-day-old piglets. In contrast, significant absorption of FITC-D70s was observed only in newborn piglets but not in 3-day-old piglets. Chromatographic analysis revealed that 125I-IGF-I represented up to 20% of total plasma radioactivity in the newborns and up to 10% in the 3-day-old piglets. The 125I-IGF-I found in the plasma was mostly bound to IGF-binding proteins. These results indicate that milk-borne IGF-I can be absorbed in neonatal piglets and the absorption is independent of gut closure.

Stability of epidermal growth factor in the gastrointestinal lumen of suckling and weaned pigs

The stability of epidermal growth factor (EGF) in the gastrointestinal humen of 3-day-old suckling and 45-day-old weaned pigs was examined by incubating iodine labeled recombinant human EGF (hEGF) in the gastrointestinal fluids at 37 degrees C and monitoring the generation of acid soluble radioactivity. Chromatographic analysis and receptor binding study were also undertaken. The results showed that hEGF was quite stable in the gastric fluids in both suckling and weaned pigs with less than 20% degradation after 20 min incubation. The degradation rate in the intestinal fluids varied with the region of the small intestine and the age of the animals. At the proximal and mid regions of the small intestine in suckling pigs the degradation rate of hEGF after 20 min incubation was 5 and 20% respectively, while the degradation rate at the distal region was up to 50%. In the small intestinal lumen in weaned pigs the degradation rate of hEGF was much greater than that in suckling pigs, and the degradation rates at the proximal, mid and distal regions were 33, 51 and 56% respectively. Addition of acid soluble or casein fractions of porcine colostrum markedly reduced the degradation of hEGF in the intestinal fluids. These results indicate that milk-borne EGF is stable in the gastric and proximal intestinal humen in suckling pigs, and may play a role in regulating postnatal development in the suckling young.

Stability of gastrin in the gastrointestinal lumen of suckling, weanling and adult pigs

It has been reported in the literature that a large quantity of gastrin is released into the gastric lumen in various species. This study was aimed to examine the stability of gastrin in the gastrointestinal (GI) lumen of pigs. Iodine-labelled little (G17) and big gastrin (G34) were incubated in vitro with the GI luminal fluids of suckling, weanling and adult pigs at 37 degrees C for 20 min, and the degradation of the peptide was measured by monitoring the generation of trichloroacetic acid soluble radioactivity. The degradation rate of G17 in the gastric fluids of all animals was less than 10%, while the degradation of G34 was less than 15% in the gastric fluids of suckling and adult pigs and about 25% in the gastric fluids of weanling pigs. The degradation rates of G17 and G34 in the small intestinal fluids of suckling pigs were between 18 and 30%, and were significantly lower than the corresponding rates in the intestinal fluids of weanling and adult pigs, the latter were between 35 and 67%. Addition of defatted porcine colostrum or its components, the casein or acid-soluble fraction, inhibited gastrin degradation in the intestinal fluids with the casein fraction having highest inhibition potency. These results indicate that gastrin is stable in the GI lumen of the suckling pigs and porcine colostrum protects gastrin from luminal hydrolysis in the small intestine, suggesting a potential physiological role of luminally released gastrin in suckling animals.

Effects of colostrum feeding on intestinal development in newborn pigs

To investigate what factors lead to rapid postnatal tissue growth and functional maturation in the newborn intestine, we compared intestinal tissue mass and digestive enzyme activities between newborn unsuckled piglets and piglets bottle fed for 3 days with either 5% lactose solution, intact porcine colostrum or trypsinized porcine colostrum. Bottle feeding of colostrum or trypsinized colostrum, but not lactose solution, led to a significant increase in the weight and length of the small intestine (p < 0.01) and a significant increase in the mucosal weight of the large intestine (p < 0.05). The mucosal protein content in the small and large intestine and the mucosal DNA content in the large intestine increased significantly following 3 days of bottle feeding of porcine colostrum or trypsinized colostrum. The total mucosal DNA contents in the small intestine of piglets fed colostrum or trypsinized colostrum were, respectively, 39 and 64% greater than that in the newborn unsuckled piglets. Intestinal digestive enzymes showed a differential response to the dietary treatment. Bottle feeding of intact porcine colostrum, but not trypsinized porcine colostrum led to a significant increase in lactase- and alkaline phosphatase-specific activities in the small intestine, while bottle feeding of lactose solution led to a significant decrease in the specific activity of lactase. In contrast, the specific activity of maltase in the small intestine increased significantly with age irrespective of dietary treatment. These results indicate that genetic and dietary factors are involved in regulating postnatal intestinal development, and porcine colostrum contains a trypsin-labile component which can increase lactase and alkaline phosphatase activities in the newborn intestine.

Development of the newborn GI tract and its relation to colostrum/milk intake: a review

During the immediate postnatal period, the gastrointestinal (GI) tract undergoes profound growth, morphological changes and functional maturation. The oesophagus shows an accelerated cell proliferation in the epithelium and an increased production and accumulation of mucus in the glands. The stomach shows a rapid tissue growth and a marked increase in acid secretion capacity. The intestine shows increased tissue growth and marked epithelial modifications; the latter include the loss of the ability by the epithelial cells of the small intestine to absorb macromolecules, and the loss of the ability by the epithelial cells of the large intestine to synthesize digestive enzymes and to absorb amino acids and glucose. These changes are apparently related to the onset of colostrum ingestion, because starved or water-fed newborns showed little changes in the GI tract. A number of hormones and growth-promoting peptides, such as insulin, cortisol, epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I), have been found at high concentrations in the maternal colostrum. There is evidence that colostrum-bone EGF and IGF-I play a role in postnatal GI development in newborns. The role of other colostrum-borne hormones and growth-promoting peptides remains to be assessed. Further studies are also required to demonstrate if colostrum-borne EGF and IGF-I can be used therapeutically to those newborns with immature or diseased GI tract, such as in cases of premature birth or prenatal growth retardation or cases requiring total parenteral nutrition.

Morphological changes in the oesophagus of newborn pigs: effects of age, diet and oral insulin-like growth factor I (IGF-I) or IGF-II

It has been reported in the literature that the stomach and the intestine in newborns undergo profound growth and functional maturation during the immediate postnatal period and diet ingestion has a significant impact on these changes. The present paper examines oesophageal development in newborn pigs during the first three postnatal days and the effects of diet and oral insulin-like growth factor I (IGF-I) or IGF-II on oesophageal morphology. It was observed that marked changes, including reduction in thickness of the epithelium, accelerated proliferation and migration of basal epithelial cells and increased accumulation of mucus in the glandular cells, occurred during the first postnatal day following onset of natural suckling. Bottle-feeding with various liquid diets (i.e. porcine colostrum, bovine colostrum, bovine milk, and infant milk formula), induced marked morphological changes which were similar to those induced by natural suckling. However, bottle-feeding with water did not result in marked reduction in the thickness of the epithelium nor did it accelerate basal epithelial cell proliferation and migration. Oral IGF-I, but not IGF-II, increased basal epithelial cell proliferation up to 81%. Owing to a large inter-animal variation, the increment did not reach a significant level (P = 0.071). The results suggest that chemical constituents in the diet and physical stimulation of food ingestion, which cause sloughing off of luminal surface tissue, are two major stimuli or epithelial cell proliferation in the new born oesophagus.

Experimental infection of newborn piglets with Yersinia enterocolitica: an animal model of enteritis

Newborn, colostrum-deprived Large White piglets infected with a human isolate of Yersinia enterocolitica biotype 4 serotype 0:3 were used as an animal model of yersiniosis. Within 3 hours of birth and before being fed, 14 piglets were inoculated orogastrically with 10 ml of bacterial suspension containing about 3 x 10(10) colony forming units of Y. enterocolitica, followed by 10 ml of 10% NaHCO3 solution. A further 14 litter mates acted as controls. The animals were reared on an artificial milk formula and humanely killed at 3 or 5 days after infection. Of the 14 infected piglets, 11 became anorexic, five vomited and 13 developed diarrhoea. Yersinia enterocolitica was isolated from their faeces and small intestinal contents. Body weight gains and the plasma glucose concentrations were significantly lower in the infected piglets than in the controls. Damage to the mucosa was observed in the whole gastro-intestinal tract, but was more severe in the small intestine and caecum. Micro-abscesses surrounding bacteria were present at the base of the villi in all parts of the small intestine, particularly in the distal ileum. Lesions were present in the small intestine in all infected piglets by day 3 and were more extensive by day 5. The liver was damaged by day 5, but not day 3. Similar lesions were seen in the mucosa of the stomach in one of six piglets at 3 days and in two of eight piglets at 5 days. It is hypothesised that the hypoacidity in the newborn stomach, as well as the administration of the NaHCO3 solution, may have produced favourable conditions for bacterial invasion.

Effects of Yersinia enterocolitica infection on growth of the body and internal organs in newborn colostrum-deprived piglets

Yersinia enterocolitica enteritis in newborn, colostrum-deprived piglets fed a human milk formula caused a reduced milk intake and decreased gain in weight but not length of the body. In infected piglets, the weight of the liver was less than in controls but other abdominal organs were unaffected. The weight of the caecum and small intestinal muscle were greater, but the length and weight of the small intestine and colon were not different. In infected piglets, the RNA concentration of the small intestinal mucosa was elevated whereas the concentrations of DNA and protein were unchanged, and total lactase activity was reduced. After antibiotic therapy, the liver weight was greater and the body weight increased at the same rate as the controls but was still lower at 14 days. The body weight of the control piglets increased linearly over the 14 days after birth. The stomach, pancreas and spleen grew more rapidly, but the liver more slowly, than the body as a whole but the kidneys had a minimum relative weight at 5 days. The total lactase activity and protein and RNA concentrations of the small intestinal mucosa decreased with age, the RNA to a greater extent than the protein.

Impact of intrauterine growth retardation on the gastrointestinal tract and the pancreas in newborn pigs

Effects of intrauterine growth retardation (IUGR) on the gastrointestinal tract and the pancreas were examined using a model of piglets with naturally occurring IUGR. IUGR was associated with significant reductions in gastrointestinal and pancreatic tissue weights. The reduction in tissue weight in the gastrointestinal tract was due to lowered cell numbers and was proportionate to the body as a whole. In contrast to the gastrointestinal tract, the reduction in the pancreas was due to both lowered cell numbers and smaller cell size and was disproportionately greater than the body as a whole. IUGR was associated with precocious occurrence of maltase and sucrase activities in the small-intestinal mucosa. The exocrine cells of the pancreas in the animals with IUGR appeared immature when compared with those in normal piglets. Further studies are required to examine the postnatal effects of IUGR on the gastrointestinal tract, the pancreas, and somatic development.

Effects of oral IGF-I or IGF-II on digestive organ growth in newborn piglets

To study whether colostrum-borne growth factors are responsible for the rapid GI tissue growth in naturally suckled newborn animals, newborn unsuckled piglets were bottle-fed for 24 h with infant milk formula with or without addition of 2 micrograms/ml of recombinant human insulin-like growth factor-I (IGF-I) or insulin-like growth factor-II (IGF-II), a level which approximated that of porcine colostrum. The animals were then sacrificed for measurements of their digestive organ weights and contents of protein, RNA and DNA in the organs. The treatment with IGF-I or IGF-II failed to show any significant effect on the weight of the esophagus, stomach, small intestine, large intestine, mandibular glands, kidneys and the spleen, and had no effects on the contents of protein, RNA and DNA in the small intestinal mucosa, the liver and the spleen. However, piglets fed with infant formula containing IGF-I (n = 7) or IGF-II (n = 7) had a heavier pancreas (p < 0.05) compared to formula-fed controls (n = 7). The DNA content in the stomach and the pancreas were greater in animals treated with IGF-I or IGF-II than in controls. Using a cell labelling technique it was shown that both IGF-I and IGF-II stimulated cell proliferation in the small intestinal crypts. The results indicate that the substantial GI tissue growth reported in newborn animals is unlikely due to colostrum-borne IGF-I or IGF-II alone. On the other hand the study does suggest that oral IGF-I and IGF-II are capable of stimulating cell proliferation in the GI tract.

Growth and morphological changes in the small and the large intestine in piglets during the first three days after birth

Growth and morphological changes in the small and the large intestine of piglets were examined during the first three days after birth. There was a 72% increase in small intestinal weight, virtually all of which occurred during the first day and was due primarily to a 115% increase in the weight of the mucosa. Associated with the tissue weight gain there was a 24% increase in small intestinal length, a 15% increase in small intestinal diameter, a 33-90% increase in villus height and a 14-51% increase in villus diameter, during the first day. The cellular population in the small intestinal mucosa, as indicated by its DNA content, increased progressively with age, and at three days had increased by 84-154%. The percentage increase in mucosal DNA content was highest in the duodenum, intermediate in the jejunum and lowest in the ileum. Histological features and tissue protein contents revealed a transient epithelial cellular swelling related to intracellular accumulation of protein on the first day. Protein accumulation was evident in the jejunum and ileum but not in the duodenum. The positions of the nuclei in the epithelial cells suggested that on the first day protein absorption was at a more advanced stage in the jejunum and the proximal ileum than in the distal ileum. Large intestinal weight increased by 33% during the first day and had doubled by the third day, and this weight gain was due to both mucosal and non-mucosal tissue growth. Villus-like structures were observed in the caecum and the proximal colon in piglets at birth and one day after birth but not in piglets three days after birth. It is speculated that such villus-like structures may have a functional significance during the transition to complete dependence on oral nutrition in newborns.

Growth and morphological changes in the stomach of newborn pigs during the first three days after birth

Growth and morphological changes in the stomach of newborn pigs were examined during the first 3 days after birth. The stomach grew disproportionately faster than the body as a whole during this period. The growth was due to hyperplasia and hypertrophy during the first day and mainly to hyperplasia thereafter as gastric DNA content increased progressively after birth, and the protein:DNA and RNA:DNA ratios increased only on the first day. Histological and morphometric analyses revealed that the growth was more pronounced in the gastric body region than in the cardiac and pyloric regions, and more pronounced in the mucosal layer than in other layers. The percentage of mucosal volume occupied by parietal cells (volume density) and the number of parietal cells per unit volume of gastric mucosa (numerical density) increased significantly 3 days after birth in the cardiac and body regions, but not in the pyloric region, of the stomach. The observed morphological changes coincide with the known pattern of functional maturation during the immediate postnatal period. It is suggested that a high level of circulating gastrin and oral ingestion of milk-derived growth factors in the newborn pig contribute to these changes.

Gastrin metabolism in neonatal pigs and grower-pigs

1. Half-life (1.7 +/- 0.1 min), distribution volume (146 +/- 12 ml/kg) and metabolic clearance rate (28 +/- 1 ml/kg/min) of little gastrin (G17) in neonatal pigs (N = 6; 3-12 days old) were significantly different from those in grower-pigs (N = 4; 161-170 days old) (2.4 +/- 0.1 min; 58 +/- 2 ml/kg; 7.9 +/- 0.3 ml/kg/min, respectively). 2. Half-life (33 +/- 4 min) and distribution volume (265 +/- 33 ml/kg) of big gastrin (G34) in neonatal pigs were greater but not significantly different from those in grower-pigs (24 +/- 2 min; 217 +/- 20 ml/kg, respectively). 3. Half-life of G17 in liver extracts from pigs 2-90 days old (40.4 +/- 4.2 min) was significantly longer than in kidney extracts (22.0 +/- 1.7 min). Half-lives of G34 in liver and kidney extracts from pigs 10-90 days old (78 +/- 6; 74 +/- 4 min, respectively) were significantly shorter than the corresponding values for 2-day-old pigs (134 +/- 3; 149 +/- 9 min, respectively). 4. Since G34 is the major circulating form of gastrin in neonatal pigs the relative longer half-life of G34 to G17 in these animals may contribute to the higher circulating gastrin concentration compared with that in older animals.

Gastrin in fetal and neonatal pigs

1. The concentration and molecular profile of gastrin were examined in plasma and tissue extracts of fetal and neonatal pigs from 93 days gestation up to 12 weeks of age and also in the fetal gastric contents. 2. Gastrin was present in the gastrointestinal tract and plasma of fetal pigs at 93 days gestation. The concentration in both plasma and antral extracts increased progressively up to birth and continued to rise postnatally, reaching a peak at about 3 weeks of age in plasma and 6 weeks in the antrum. 3. In blood the major molecular form of gastrin was G34 (up to 80%), while in the antrum the major form was G17 (66-91%). The percentage of G34 in the antrum was highest in later gestation (21%), and reached adult proportion by 8 weeks of age (4%). 4. A considerable amount of gastrin, chiefly G17, was detected in the fetal gastric contents. Synthetic human G17 was stable in fetal gastric contents when incubated at 37 degrees C for 60 min, although, when incubated with gastric contents from a sow, it disappeared within 5 min. 5. It is suggested that the presence of gastrin in fetal gastric contents may be important in stimulation of fetal gut development.

Detection of circulating immune complexes with polyethylene glycol precipitation F(ab')2 anti-C3 ELISA

A polyethylene glycol (PEG) precipitation F(ab')2 anti-C3 ELISA for the detection of complement-fixing IgG circulating immune complexes (CIC) is described. For this assay, test sera were treated with 3.5% PEG and then measured with F(ab')2 anti-C3 ELISA. The lower detection limit was 4 micrograms/ml of heat aggregated human IgG (HAHG). Intra-assay coefficient of variation (CV) was 4.9-8.3%. High levels of CIC are found in the sera of patients with systemic lupus erythematosus (SLE), hepatitis B and stomach cancer.

Estrogen receptors in the adrenal cortex of the possum (Trichosurus vulpecula)

1. Specific [3H]estradiol binding activity with characteristics of estrogen receptors was found in the cytosols and nuclear extracts of the adrenal cortex proper and special zone of the brushtail possum (Trichosurus vulpecula). 2. The specific estradiol receptor had a sedimentation coefficient on sucrose gradients of approximately 9S and a molecular weight on gel filtration of more than 200,000. The adrenal cortex cytosol binds [3H]estradiol with high affinity (Ka 5.5 X 10(9) M-1), and limited capacity (Bmax 62.7 fmol/mg cytosol prot). In competition experiments with different steroids the receptor showed a high affinity for four estrogens and a very low affinity to androgens, progesterone and cortisol. 3. There was no difference in the affinity and maximum binding capacity of the cytosols from cortex proper in male and female animals, but the binding capacity of the special zone of females was half that of cortex proper. Estradiol receptors were found in the kidney, liver, lung, testis and muscle but only in the adrenal and prostate was the binding capacity relatively high compared with the uterus. 4. The specific binding capacity of [3H]estradiol to cytosols of adrenal cortex at different stages of the estrus cycle and pregnancy was unrelated to that of the uterus. In the adrenal the receptor concentration was lowest at estrus, when uterine concentration was high, while in late pregnancy the binding of adrenal cortex and uterus cytosols was almost the same. 5. The possible physiological significance of the presence of a specific estrogen receptor in male and female possums is discussed.

Dose finding double-blind clinical trial with praziquantel in schistosomiasis japonica patients

A double-blind clinical trial with praziquantel was carried out. A total of 400 cases was treated with four different dosages, namely, 60, 50, 40 and 30 mg/kg body weight of praziquantel. The drug was given in one day divided into two doses. Identical placebo tablets were used to make up a total of 60 mg/kg. Tolerance was good in all with the exception of one case suffering from asthmatic attack with papule rashes over large area of the body surface. 394 patients were able to be followed up parasitologically six months post-treatment. 79.8%, 71.7%, 78.8% and 70.1% of the patients were negative in the groups with the total dose of 60, 50, 40 and 30 mg/kg respectively. The cure rates as well as the side effects were similar for the four groups. The efficacy was lower than that reported by other authors and the possibility of reinfection was incriminated. In villages with few snails the negative hatching rates in aforementioned four groups were 89.1%, 91.1%, 88.9% and 81.8%, while in villages with abundant snails the rates were 68.2%, 46.5%, 66.7% and 54.8%. The difference between the two areas was statistically significant. Higher efficacy was observed in adults with an average cure rate of 80.0% than in children under 15 years of age, the average cure rate being 57.1%.(ABSTRACT TRUNCATED AT 250 WORDS)