Suckling Stage Research Articles

母親ラットを介して投与されたゲニステインの乳仔ラットの骨形成に対する影響

The effects of the soy-isoflavone, genistein, on the osteogenesis of rat dams and their offspring were evaluated. Maternal rats were fed on a diet containing purified genistein at the level of 0.5g/kg of diet or on a control diet without genistein from various stages during pregnancy to postnatal day 12. The dry weight, length, ash weight, mineral content, calcium content, and bone mineral density of the femurs from the dams and infants were measured. Genistein slightly affected the bone of infants immediately after the birth, but the effect was temporary on infant osteogenesis.There was no consistent effect on the infants after successive genistein exposure through their mothers during the fetal and suckling stages, and there was no difference in effect according to the period of exposure during pregnancy and lactation. The femurs of the dams ingesting genistein during the pregnancy period showed a significantly higher calcium content, but there was no significant effect on the dry weight, ash weight, mineral content or bone mineral density.The results of this study suggest that maternal feeding of genistein had no marked effect on osteogenesis in the dams, suckling pups and offspring during growth.

Asphyxia due to pacifiers—case report and review of the literature

Pacifiers and bottle nipples entail the risk of asphyxia when they are swallowed, self-made or have become porous, or when used by older children whose teeth and chewing musculature have developed beyond the suckling stage. A further danger lies in the various devices used to tie the pacifier to the child, as they can cause strangulation. On the basis of this first case of a 2-year-old biting off a piece of her pacifier and fatally aspirating it, we point to the dangers and security requirements related to pacifiers and bottle nipples, and give a review of the related literature.

Vertical and horizontal transmission of intestinal commensal bacteria in the rat model

The intestinal microbiota of 10 pups (five from dam A and five from dam B) in the suckling stage (18 days old) and at maturity (40 days old) were compared with those of their dams to assess the mechanisms of bacterial transmission during development of intestinal microbiota in the rat model. Fecal samples were subjected to amplified ribosomal DNA restriction analysis and 65 operational taxonomic units (OTUs) were identified. The intestinal microbiota of mature pups were more complex than those of the suckling stage. Most of the OTUs present in dams were detected in their pups at maturity. These common OTUs accounted for more than 70% of the clones of libraries generated from both groups of pups. In contrast, the number of OTUs in pups that were not shared by their dams was larger than the number they had in common. These bacteria were presumably transmitted horizontally from environmental sources. However, these OTUs accounted for less than 30% of the clones generated from both groups of pups. This study suggested that vertically transmitted bacteria were the predominant component of the intestinal microbiota of pups, although the diversity of intestinal microbiota during pup growth was influenced by horizontal transmission.

Flight distance of dairy cows and its relationship to daily routine management procedures and productivity

ABSTRACTThe objectives of this study were to determine to what extent the flight distance of cows to humans was influenced by sire and management procedures before and after maturity, and whether there was a correlation between the flight distance and productivity on commercial dairy farms. Flight distance of 84 Holstein cows, the stockperson's daily routine management procedures and production performance were recorded repeatedly on eight commercial dairy farms. The management procedures for the animals at the suckling, growing, lactating and dry stages were classified into four categories by degree of tactile interactions between the stockperson and the animal: hand procedures with touch on (category A), nearby (category B) and apart (category C) from the animal, and machinery procedures (category D). There was no apparent sire effect on flight distance (P = 0.08), whereas the flight distance ranged from 1.17 ± 0.86 to 4.47 ± 2.01 m by farm (P < 0.01), and gradually shortened with repetition (P < 0.05). Regression analysis indicated that the length of time of category B at the suckling stage and category B at the dry stage accounted for 37% and 32% of the variation in flight distance, respectively. As for the total time of the four procedure categories, growing stage was the prime predictor of flight distance, which accounted for 36% of the variation. Flight distance tended to correlate with the first calving age (r = 0.66, P = 0.07). These results suggest the importance of non‐producing periods, before maturity and during the dry period, on the subsequent and lifelong advantages of a good relationship between the stockperson and their animals.

Endocytosis by absorptive cells in the middle segment of the suckling rat small intestine.

In neonatal suckling rats, the absorptive cells of the duodenum, jejunum and ileum endocytose maternal milk macromolecules, including antibodies from the lumen. To determine whether the absorptive cells from the middle segment of small intestine have an apical endocytic membrane system that is the same as that of the duodenum, jejunum or ileum, we applied horseradish peroxidase by intraluminal injection, and examined the absorptive cells using light and transmission electron microscopy. In the middle segment of the small intestine, the absorptive cells had an apical endocytic membrane system including apical coated pits, apical invaginations, coated vesicles, vesicles, tubules, early endosomes, late endosomes and a large homogeneous electron-dense lysosome at the supranuclear region. This would suggest that the endocytic membrane system in the absorptive cells from the middle segment of the small intestine is specialized for quick and active intracellular digestion. The apical endocytic membrane system of the absorptive cells varied according to the segment of the small intestine, and the absorptive cells made their transition gradually from jejunal type to middle type, and then from middle type to ileal type at the suckling stage. The jejunal and ileal type of absorptive cells increased with growth, in contrast to the middle type.

Postnatal ontogeny of kinetics of porcine jejunal brush border membrane-bound alkaline phosphatase, aminopeptidase N and sucrase activities

Our objectives were to determine postnatal changes in the maximal enzyme activity ( V max) and enzyme affinity ( K m ) of jejunal mucosal membrane-bound alkaline phosphatase, aminopeptidase N and sucrase using a porcine model which may more closely resemble the human intestine. Jejunal brush border membrane was prepared by Mg 2+-precipitation and differential centrifugation from pigs of suckling (8 days), weaning (28 days), post-weaning (35 days) and adult (70 days) stages. p-Nitrophenyl phosphate (0–8 mM), l-alanine- p-nitroanilide hydrochloride (0–28 mM) and sucrose (0–100 mM) were used in alkaline phosphatase, aminopeptidase N and sucrase kinetic measurements. V max of alkaline phosphatase was the lowest in the adult (4.27 μmol·mg −1 protein·min −1), intermediate in the suckling (9.75 μmol·mg −l protein·min −l) and the highest in the weaning and post-weaning stage (12.83 and 10.40 μmol·mg −l protein·min −l). K m of alkaline phosphatase was high in the suckling and weaning stages (5.14 and 9.93 mM) and low in the adult (0.66 mM). V max of aminopeptidase N was low in the suckling (7.04 μmol·mg protein −1·min −1) and high in the post-weaning stage (13.36 μmol·mg −l protein·min −l). K m of aminopeptidase N was the highest in the two weaning stages (2.96 and 3.39 mM), intermediate in the adult (2.33 mM) and the lowest in the suckling stage (1.66 mM). V max of sucrase increased from the suckling to the adult (0.48–1.30 μmol·mg −l protein·min −l). K m of sucrase ranged from 11.19 to 16.57 mM. There are dramatic postnatal developmental changes in both the maximal enzyme activity and enzyme affinity of jejunal brush border membrane-bound alkaline phosphatase, aminopeptidase N and sucrase in the pig.

Spread of hepatitis E virus among different-aged pigs: two-year survey in Taiwan.

Swine are reservoirs of hepatitis E virus (HEV). In this study, a 2-year survey of HEV in feces and sera of swine was conducted to determine if: 1) HEV has circulated among pigs for some time in Taiwan; 2) the spread of HEV among different-aged pigs; and 3) there exists HEV strains possibly imported through trading. From 1998-2000, 521 serum samples and 54 fecal specimens from pigs were examined by reverse transcription polymerase chain reaction. None of the 11 pigs in suckling stage (< 2 months) were serum HEV RNA positive. The highest viremia rate (4.5%) was in pigs of 2 months age, followed by 1.2% and 1.8% in pigs of growing (3-4 months) and finishing stages (5-6 months), and none in pigs older than 6 months. Viremia showed little variation in different years and areas. None of the 20 fecal samples from pigs in suckling stage were HEV RNA positive, whereas 9% of the 34 samples from pigs in growing or finishing stages were positive. Most swine HEV isolates in Taiwan clustered within the genotype 4, whereas the three HEV isolates cloned from pigs imported recently from the U.S. belonged to the genotype 3 HEV in the U.S. The results suggest that HEV may infect pigs at an early growing stage and spread unnoticed among pigs and possibly across countries through trading.

Intra-uterine growth restriction differentially regulates perinatal brain and skeletal muscle glucose transporters

Employing Western blot analysis, we investigated the effect of maternal uterine artery ligation causing uteroplacental insufficiency with asymmetrical intrauterine growth restriction (IUGR) upon fetal (22d) and postnatal (1d, 7d, 14d and 21d) brain (Glut 1 and Glut 3) and skeletal muscle (Glut 1 and Glut 4) glucose transporter protein concentrations. IUGR was associated with a ∼42% decline in fetal plasma glucose ( p<0.05) and a ∼25% decrease in fetal body weights ( p<0.05) with no change in brain weights when compared to the sham operated controls (SHAM). In addition, IUGR caused a ∼45% increase in fetal brain Glut 1 (55 kDa) with no change in Glut 3 (50 kDa) protein concentrations. This fetal brain Glut 1 change persisted, though marginal, through postnatal suckling stages of development (1d–21d), with no concomitant change in brain Glut 3 levels at day 1. In contrast, in the absence of a change in fetal skeletal muscle Glut 1 levels (48 kDa), a 70% increase was observed in the 1d IUGR with no concomitant change in either fetal or postnatal Glut 4 levels (45 kDa). The change in skeletal muscle Glut 1 levels normalized by d7 of age. We conclude that IUGR with hypoglycemia led to a compensatory increase in brain and skeletal muscle Glut 1 concentrations with a change in the brain preceding that of the skeletal muscle. Since Glut 1 is the isoform of proliferating cells, fetal brain weight changes were not as pronounced as the decline in somatic weight. The increase in Glut 1 may be protective against glucose deprivation in proliferating fetal brain cells and postnatal skeletal myocytes which exhibit `catch-up growth', thereby preserving the specialized function mediated by Glut 3 and Glut 4 towards maintaining the intracellular glucose milieu.

Nephrotic Mice (ICGN Strain): A Model of Diffuse Mesangial Sclerosis in Infantile Nephrotic Syndrome

The ICGN mouse strain is a unique model for naturally occurring nephrotic syndrome. In the present study, we examined the onset of the clinical manifestation of nephrotic syndrome and determined the sequence of intraglomerular events associated with progression of nephrotic conditions. Laboratory analysis revealed that homozygous (nep/nep) mice showed urinary albumin excretion during the suckling stage, rapidly leading to hypoalbuminemia accompanied by body growth failure. Renal pathology demonstrated that an initial intraglomerular event in the nephrotic mice was observed 3 weeks after birth in the form of mesangiolytic lesions, characterized by microaneurysm, platelet accumulation and capillary ballooning. In 6-week-old homozygous mice, mesangial sclerosis, characterized by mesangial expansion and glomerular hypertrophy, was observed in a diffuse fashion. Immunohistochemistry revealed that the glomerular cells in the 3-week-old homozygous suckling mice were positive for α-smooth muscle actin, suggesting a phenotypic change in the mesangial cells. Mesangial expansion, confirmed by the over-deposition of type I collagen, was evident until 6 weeks after weaning, while it was of interest that fibrogenic cytokines such as platelet-derived growth factor and transforming growth factor-β were not detected in the sclerotic glomeruli throughout the observations. Furthermore, the nephrotic features were shown to be resistant to steroid therapy with a high dose of prednisolone. Our results suggest that diffuse mesangial sclerosis, a hereditary glomerular disease, may be genetically generated through early myofibroblast formation, which occurs and develops probably independently of up-regulation of these fibrogenic cytokines. In conclusion, the homozygous nephrotic mouse (ICGN strain) is believed to be a good model for investigating not only nephrotic conditions but also cellular and molecular pathogenesis of diffuse mesangial sclerosis in steroid-resistant infantile nephrotic syndrome.

Role of CTL mutants in demyelination induced by mouse hepatitis virus, strain JHM.

Mouse hepatitis virus, strain JHM (MHV-JHM) is a well described cause of demyelination. C57B1/6 (B6) mice infected at the suckling stage in the presence of protective antibodies remain asymptomatic initially but later develop clinical disease (hindlimb paralysis). Infectious virus can be isolated from these mice. Recently, two MHV-specific target epitopes for cytotoxic CD8 T cells have been identified in B6 mice. Our results show that in all mice with hindlimb paralysis, mutations can be detected in the RNA encoding the immunodominant of the two epitopes. These mutations result in a loss of recognition by MHV-specific cytotoxic T cells. These changes are not detected, for the most part, in mice that remain asymptomatic nor in mice with acute encephalitis. These results suggest that the development of CTL escape mutants is necessary for hindlimb paralysis to develop in this model.

DEXAMETHASONE PRECOCIOUSLY INDUCES INTESTINAL SUGAR TRANSPORT IN SUCKLING RATS † 474

During normal development, intestinal fructose transport is enhanced only in postweaning (>28d) rats. Early introduction of a high fructose diet enhances fructose absorption in weaning (14-28d) but not in suckling (<14d) rats. In contrast, glucose absorption is independent of diet in both weaning and suckling stages. In this study, we determined whether Dexamethasone (DEX) would allow dietary induction of sugar transport in suckling rats. DEX, 0.4ug/g body weight (BW), was administered i.p. once daily to rat pups from d 5-9. Pups were gavage-fed on d 8-9 with sugar solutions containing high fructose (HF) and high glucose (HG) at a volume of 2% BW 2X per d. Pups stayed with dams at all other times. Control litter mates were fed similar solutions but received phosphate buffer i.p. instead of DEX. On d 10, pups were sacrificed and intestinal uptake studies using the everted sleeve technique were performed. Two-way analysis of variance (ANOVA) showed that fructose uptake increased 3X in DEX-treated pups fed HF (P<0.0001) but only 2X in DEX-treated pups fed HG (P<0.0001) over control. There was also a 2X significant increase in glucose uptake in DEX-treated pups fed HG(P<0.0001) and HF (P<0.0001). Uptakes were 2-3X greater in the proximal and middle than in the distal small intestine. DEX-treated pups failed to gain weight compared to control (P<0.0001). There was no statistically significant difference in intestinal lengths and weights across treatment groups. DEX therefore non-specifically enhances transport of nutrients and also allows specific induction of fructose transporters by its substrate. The proximate mechanism of this DEX effect remains unclear and is a subject of future research.

新生児期及び乳児期早期の気道過敏性とぜん鳴

新生児期及び乳児期早期の気道過敏性とぜん鳴

Lectin histochemistry in rabbit appendix epithelial cells during suckling and weaning, and in adults

Summary A study was made of the modification of glycoconjugates in rabbit appendix epithelium, including vacuolated cells on fetal villi, columnar absorptive cells (enterocytes) and lymphoid follicle associated epithelial (FAE) cells during the suckling, weaning and adult stages by lectin histochemistry. Sections were incubated with seven biotinyl lectins: DBA, SBA, WGA, PNA, UEA-I, ConA and RCA-I. Gradual and progressive changes were observed in the appendix epithelial glycoconjugates during postnatal development. Three groups of lectins were classified according to the lectin binding pattern. SBA, DBA and UEA-I lectins constantly stained FAE cells and enterocytes during suckling. In particular, SBA and UEA-I stained to the same extent as in weaning and adults. In contrast, the staining of DBA for FAE cells gradually decreased and almost ceased to be evident at 2 months. In the binding of PNA, FAE cells were negative or showed very slight reactivity at all developmental stages. Staining by ConA, WGA and RCA-I of FAE cells and enterocytes was virtually the same. Significant differences were not observed at any stage of development.

Thyroidal regulation of lingual lipase development in suckling rats.

Rat lingual lipase undergoes maturational increases during postnatal development. The role of thyroxine (T4) in the control of lingual lipase during development was evaluated. T4 given at an early suckling stage (starting day 4 or 5) moderately increased lingual lipase (20-30%) compared to age-matched controls. A similar dose of T4 given later (age > 2 weeks) was ineffective. The T4-sensitive period coincides with a time of low circulating T4, suggesting a role of T4 in modulating the development of lingual lipase in rat pups. Since simultaneous treatment with U486, a type II glucocorticoid receptor antagonist only partially blocked the T4 induction of lingual lipase, T4 appeared to have a direct action on the lingual gland. Pups of propylthiouracil (PTU)-treated dams (previously found to be hypothyroid) showed a delay in the maturation of lingual lipase compared to age-matched pups whose dam was not given PTU. Pups were most sensitive to PTU in the early suckling stage. PTU-induced delayed maturation of lingual lipase was a result of hypothyroidism, since T4 replacement when given early (at the age of 5 days) abolished most of the effect of PTU. When T4 was given later (at the age of 10 days), recovery was much less. This suggests the presence of an early period that is critically dependent on T4 for the full expression of lingual lipase in the rat tongue serous glands.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine lipoprotein and apolipoprotein profiles as influenced by sex and growth

Three (intact) Angus males and females that were half-sibs and born within 21 d of each other were selected for this study. Each animal was bled periodically from birth to slaughter (18 mo) to determine the qualitative composition of plasma lipoproteins and apolipoproteins during its growth and development. Major components observed were: 1) very low-density (VLDL), 2) low-density (LDL), and 3) high-density lipoproteins (HDL). Individual amounts of triglycerides, cholesterol, and proteins for the VLDL were not different (P greater than .05) between sexes at any time during growth and development. At 1 yr of age and 15 mo of age, females had significantly larger (143.4 and 93.5 mg/dl) amounts of protein in the HDL than males (67.0 and 93.5 mg/dl), respectively. Within the male group, the LDL triglyceride concentration of calves was significantly (P less than .05) higher (7.4 mg/dl) than at all other bleeding times. Within the female group, cholesterol values for the VLDL were significantly (P less than .05) larger as calves and weanlings (16.5 and 21.7 mg/dl respectively) than for other bleeding periods. At all stages of growth and development, the HDL apoprotein profiles showed a distinct band with a weight of about 28,000 Da, which represented apolipoprotein-A-I. During the suckling stage, pooling of LDL fractions provided two components on the acrylamide gel (7.5 to 20%), apolipoprotein-B and a low molecular weight band. At 12 and 15 mo, no low molecular weight band was present in the pooled LDL fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related accumulation of heavy metals in bone of the striped dolphin, Stenella coeruleoalba

Concentration levels of metals (Fe, Mn, Zn, Cu, Pb, Ni, total Hg, methyl Hg and Se) in whole bone of the striped dolphin, Stenella coeruleoalba, and their variations with growth and sex were investigated. The metal concentrations characteristically changed with bone growth. Accumulation of Fe, Mn, Zn and Cu depended upon the metabolic turnover connected with ossification whilst, for the accumulation of Pb, Ni, Cd and Hg, the age or exposure time was a dominant factor. However, Pb and Ni were markedly accumulated during the suckling period and probably transferred from mother to calf via milk. The Cd concentration rapidly increased during the late period of the suckling stage, indicating higher absorption efficiency and accumulation of Cd through the digestive tract of the calf than those of mature dolphin. The transfer of total Hg to calf via milk was negligible, and its concentration increased with age until about 20 years, while methyl Hg reached a plateau at about 10 years. A significant positive correlation ( r = 0·798, p < 0·01) was found between the concentrations of total Hg and Se in the bone, and the molar ratio depended upon that of the blood. Furthermore, the concentrations of Fe and Cd in the bone were higher in the female than in the male, while Pb and Ni were lower in the female; they are probably due to parturition and lactation.

Epigenetic Asymmetry as an Ecological Indicator in Muskrats

Fluctuating asymmetry in numbers of nerve foramina in the skull was studied in nine Finnish populations of the muskrat, Ondatra zibethicus ( n = 555). A high negative correlation ( r =−0.94) was found between the population means of asymmetry and suitability of habitat as reflected in growth indices (carcass weight/age) of the animals. This relationship is weaker among individuals within populations. The results support the idea of stress-induced interference in the synchronization of normal ontogeny of bilaterally symmetric structures during embryonic or suckling stages, although this still needs to be confirmed experimentally. Genetic differences among populations seem improbable as an explanation of fluctuating asymmetry.

Mercury and Selenium Levels at the Fetal and Suckling Stages of Striped Dolphin,Stenella coeruleoalba

Mercury and Selenium Levels at the Fetal and Suckling Stages of Striped Dolphin,<i>Stenella coeruleoalba</i>

Mercury and selenium levels at the fetal and suckling stages of striped dolphin, Stenella coeruleoalba.

The concentrations of mercury and selenium in thirteen tissues of the fetuses and sucklings of striped dolphin (Stenella coeruleoalba) were examined. A large portion of the mercury in the fetuses and sucklings was present in the methylated form. The total mercury level in the liver of the fetuses was slightly higher than in the other tissues. In half of the tissues, the total mercury levels were lower in the sucklings than in the fetuses. Although the selenium level in the fetuses was the highest in the liver, that in the sucklings was slightly higher in the blubber than in other tissues. In most tissues, the selenium level at the suckling stage was higher than at the fetal stage. A highly significant correlation was detected between the total mercury and selenium burdens in the fetuses. Linear relationships were observed between the body weight and total mercury burden and between the body weight and selenium burden of fetuses. The total burden of methylmercury in the term fetuses was around 1 % of those...

An immunohistochemical and ultrastructural study of Segi's cap, a large aggregation of gut endocrine cells, in bovine fetuses.

Segi's cap, a large aggregation of basal-granulated cells at the top of the intestinal villus, was studied in the proximal small intestine of bovine fetuses by histological, immunohistochemical and ultrastructural techniques. 1) Typical Segi's caps were seen in the duodenum and proximal jejunum in bovine fetuses. 2) Smaller groups of basal-granulated cells were found in the villous and partly also in the cryptal epithelium, as well as in the subepithelial lamina propria. The possible mechanism for their occurrence was discussed in connection with the fate of the cap. 3) Segi's caps were present in a neonatal calf before the suckling stage, but not in 3 or 4 week-old calves. The process of and reason for this abrupt disappearance of the caps are unknown. 4) The Segi's cap in bovine fetuses consisted mainly of argyrophil cells as demonstrated by Grimelius' and Hellerström-Hellman's silver methods. Only a few argentaffin cells were found in fetal caps using a modified Masson-Hamperl's silver method. 5) Immunohistochemically, somatostatin-, gastrin-, motilin- and secretin-immunoreactive cells were identified. 6) Four different endocrine cell types could be distinguished in the bovine Segi's cap on the basis of the ultrastructural appearance of their secretory granules.