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1.
Twenty-one healthy bottle-fed infants were screened monthly (1-4 months) for bifidobacteria in their stools. Bifidobacteria were detected by culture and isolates specified by PCR. Alternatively, direct PCR in undiluted fecal suspensions was carried out for detection of bifidobacteria under the cultural detection level. All infants harbored cultivable bifidobacteria throughout the study period. Beerens medium was shown to permit a better recovery of bifidobacteria than MRS and horse blood Columbia agar. Direct PCR detection proved valuable in detecting species for which no cultural isolate could be recovered since the species were under the cultural detection level. B. bifidum, B. longum-infantis and B. breve were confirmed as dominant and stable species in infant stools while B. adolescentis and B. catenulatum group exhibited unstable colonization profiles. A trend towards B. breve decrease began at month 3 while carriage of the B. catenulatum group and B. adolescentis was rising. This observation warrants further analysis to assess a possible switch occurring at month 3 in bottle-fed infants, between so-called infant and adult bifidobacterial species.  相似文献   

2.
The characteristics of electron drift in a mixture of argon with mercury vapor at reduced electric fields of E/N = 1–100 Td are calculated and analyzed with allowance for inelastic collisions. It is shown that even a minor additive of mercury to argon at a level of a fraction of percent substantially affects the discharge parameters, in particular, the characteristics of inelastic processes. The influence of the concentration of mercury vapor in argon on the kinetic characteristics, such as the diffusion and mobility coefficients and ionization frequency, is investigated.  相似文献   

3.
Journal of Physiology and Biochemistry - Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later...  相似文献   

4.
The DNA mismatch repair (MMR) protein dimer MutLα is comprised of the MutL homologues MLH1 and PMS2, which each belong to the family of GHL ATPases. These ATPases undergo functionally important conformational changes, including dimerization of the NH2-termini associated with ATP binding and hydrolysis. Previous studies in yeast and biochemical studies with the mammalian proteins established the importance of the MutLα ATPase for overall MMR function. Additionally, the studies in yeast demonstrated a functional asymmetry between the contributions of the Mlh1 and Pms1 ATPase domains to MMR that was not reflected in the biochemical studies. We investigated the effect of mutating the highly conserved ATP hydrolysis and Mg2+ binding residues of MLH1 and PMS2 in mammalian cell lines. Amino acid substitutions in MLH1 intended to impact either ATP binding or hydrolysis disabled MMR, as measured by instability at microsatellite sequences, to an extent similar to MLH1-null mutation. Furthermore, cells expressing these MLH1 mutations exhibited resistance to the MMR-dependent cytotoxic effect of 6-thioguanine (6-TG). In contrast, ATP hydrolysis and binding mutants of PMS2 displayed no measurable increase in microsatellite instability or resistance to 6-TG. Our findings suggest that, in vivo, the integrity of the MLH1 ATPase domain is more critical than the PMS2 ATPase domain for normal MMR functions. These in vivo results are in contrast to results obtained previously in vitro that showed no functional asymmetry within the MutLα ATPase, highlighting the differences between in vivo and in vitro systems.  相似文献   

5.
We determined the independent factors that reflect the fundamental characteristics of the functional state (FS) in adolescents aged 13–14 years (n = 162): the sympathetic regulation and parasympathetic regulation of FS, physical working capability; the efficiency of cognitive performance; the hemodynamic basis of cognitive activity; nonspecific resistance to upper respiratory tract infections. Using the systematic approach, we investigated the physiological basis of these factors and determined the indices suitable for estimating the FS of adolescents at different stages of puberty. We observed progressive dynamics of FS parameters related to factors listed above in boys of the same chronological age at different puberty stages. Beginning from stage II to stage IV, we observed a heterochronic and nonlinear decrease in the tension of system of autonomic FS regulation, an increase in the efficiency of cognitive activity and its hemodynamic supply, as well as an improvement of anaerobic working capability.  相似文献   

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Dynamic features of Ca2+ interactions with transport and regulatory sites control the Ca2+-fluxes in mammalian Na+/Ca2+(NCX) exchangers bearing the Ca2+-binding regulatory domains on the cytosolic 5L6 loop. The crystal structure of Methanococcus jannaschii NCX (NCX_Mj) may serve as a template for studying ion-transport mechanisms since NCX_Mj does not contain the regulatory domains. The turnover rate of Na+/Ca2+ exchange (kcat = 0.5 ± 0.2s−1) in WT–NCX_Mj is 103–104 times slower than in mammalian NCX. In NCX_Mj, the intrinsic equilibrium (Kint) for bidirectional Ca2+ movements (defined as the ratio between the cytosolic and extracellular Km of Ca2+/Ca2+ exchange) is asymmetric, Kint = 0.15 ± 0.5. Therefore, the Ca2+ movement from the cytosol to the extracellular side is ∼7-times faster than in the opposite direction, thereby representing a stabilization of outward-facing (extracellular) access. This intrinsic asymmetry accounts for observed differences in the cytosolic and extracellulr Km values having a physiological relevance. Bidirectional Ca2+ movements are also asymmetric in mammalian NCX. Thus, the stabilization of the outward-facing access along the transport cycle is a common feature among NCX orthologs despite huge differences in the ion-transport kinetics. Elongation of the cytosolic 5L6 loop in NCX_Mj by 8 or 14 residues accelerates the ion transport rates (kcat) ∼10 fold, while increasing the Kint values 100–250-fold (Kint = 15–35). Therefore, 5L6 controls both the intrinsic equilibrium and rates of bidirectional Ca2+ movements in NCX proteins. Some additional structural elements may shape the kinetic variances among phylogenetically distant NCX variants, although the intrinsic asymmetry (Kint) of bidirectional Ca2+ movements seems to be comparable among evolutionary diverged NCX variants.  相似文献   

8.

Background

The aim of this study, conducted in Europe, was to develop a validated risk factor based model to predict RSV-related hospitalisation in premature infants born 33–35 weeks'' gestational age (GA).

Methods

The predictive model was developed using risk factors captured in the Spanish FLIP dataset, a case-control study of 183 premature infants born between 33–35 weeks'' GA who were hospitalised with RSV, and 371 age-matched controls. The model was validated internally by 100-fold bootstrapping. Discriminant function analysis was used to analyse combinations of risk factors to predict RSV hospitalisation. Successive models were chosen that had the highest probability for discriminating between hospitalised and non-hospitalised infants. Receiver operating characteristic (ROC) curves were plotted.

Results

An initial 15 variable model was produced with a discriminant function of 72% and an area under the ROC curve of 0.795. A step-wise reduction exercise, alongside recalculations of some variables, produced a final model consisting of 7 variables: birth ± 10 weeks of start of season, birth weight, breast feeding for ≤ 2 months, siblings ≥ 2 years, family members with atopy, family members with wheeze, and gender. The discrimination of this model was 71% and the area under the ROC curve was 0.791. At the 0.75 sensitivity intercept, the false positive fraction was 0.33. The 100-fold bootstrapping resulted in a mean discriminant function of 72% (standard deviation: 2.18) and a median area under the ROC curve of 0.785 (range: 0.768–0.790), indicating a good internal validation. The calculated NNT for intervention to treat all at risk patients with a 75% level of protection was 11.7 (95% confidence interval: 9.5–13.6).

Conclusion

A robust model based on seven risk factors was developed, which is able to predict which premature infants born between 33–35 weeks'' GA are at highest risk of hospitalisation from RSV. The model could be used to optimise prophylaxis with palivizumab across Europe.  相似文献   

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Correctly estimating the trophic fractionation factors (Δ15N and Δ13C) in controlled laboratory conditions is essential for the application of stable isotope analysis in studies on the trophic structure of soil communities. Laboratory experiments usually suggest large 15N/14N and small 13C/12C trophic fractionation, but in field studies litter-dwelling microarthropods and other invertebrates are consistently enriched in 13C relative to plant litter. In the present study, we report data from two laboratory experiments investigating both fungi–collembolans and litter–fungi–collembolans systems. In the fungi–collembolans system, Δ15N and Δ13C averaged 1.4 ± 0.1 and 1.0 ± 0.2 ‰, respectively. In microcosms with fungi-inoculated litter, the difference in δ15N between collembolans and plant litter averaged 1.5 ± 0.2 ‰, confirming the relatively small 15N/14N trophic fractionation at the basal level of detrital foodwebs reported in numerous field studies. In full agreement with field observations, the difference in δ13C between bulk litter and collembolans in laboratory microcosms averaged 3.6 ± 0.1 ‰ and only little depended on collembolan species identities or the presence of water-soluble compounds in the litter. We conclude that increased δ13C values typical of litter-dwelling decomposers are largely determined by an increased 13C content in saprotrophic microorganisms.  相似文献   

11.
A male child hospitalized due to undescended testes (cryptorchism) was found to possess an abnormal autosome with an unusually elongated short arm in group 13–15. A familial chromosome investigation undertaken in 14 persons related to the propositus in his paternal line and in his mother revealed that his clinically normal father, grandfather, 2 aunts and a female cousin carried the same aberrant autosome. It is evident that a carrier of the abnormal chromosome is the grandfather, that the anomalous element was transmitted, irrespective of sex, from the parents either one of whom carried the aberrant one, and that the particular autosomal abnormality is not always associated with specific phenotypic anomaly. A possible origin of the aberrant autosome is discussed.Contribution no. 733 from the Zoological Institute, Faculty of Science, Hokkaido University, Sapporo.The senior author (S. M.) wishes to dedicate this paper to Dr. Jakob Seiler on the occasion of his 80th birthday, May 16, 1966.  相似文献   

12.
1. The characteristics of acid and neutral beta-galactosidases isolated chromatographically from homogenates of the mucosa of the jejunum and ileum of suckling rats were studied. 2. The minimal molecular weight of the acid beta-galactosidase, as estimated by gel filtration on Sephadex G-200, was in the range 83000-105000, whereas for the neutral beta-galactosidase the estimated molecular weight was in the range 360000-510000. 3. The acid and neutral beta-galactosidases were inhibited competitively by galactono-(1-->4)-lactone, with respective K(i) values of 0.15mm and 1.1mm. Only the acid beta-galactosidase was inhibited competitively by sodium galactonate (K(i) 0.17mm). 4. Heat inactivation of both beta-galactosidases occurred according to first-order kinetics. The neutral enzyme was more labile, but bovine serum albumin protected acid enzyme only. 5. Urea treatment inactivated both beta-galactosidases, the neutral beta-galactosidase being more sensitive than the acid beta-galactosidase. 6. No differences were found between preparations from the jejunum and ileum.  相似文献   

13.
The planar cell polarity (PCP) signaling pathway, principally understood from work in Drosophila, is now known to contribute to development in a broad swath of the animal kingdom, and its impairment leads to developmental malformations and diseases affecting humans. The ‘core’ mechanism underlying PCP signaling polarizes sheets of cells, aligning them in a head-to-tail fashion within the sheet. Cells use the resulting directional information to guide a wide variety of processes. One such process is lateralization, the determination of left–right asymmetry that guides the asymmetric morphology and placement of internal organs. Recent evidence extends the idea that PCP signaling underlies the earliest steps in lateralization and that PCP is invoked again during asymmetric morphogenesis of organs including the heart and gut.  相似文献   

14.
The aim of this study is to obtain a reference point for early detection of tumors in individuals whose spouses were diagnosed with malignant tumors. Data from 230 husband and wife pairs with malignant tumors were collected and analyzed from the family history records of 15,000 people who came to the Department of Cancer Prevention, Cancer Institute/Hospital, Chinese Academy of Medical Sciences for cancer screening between January 2009 and May 2012. The median diagnosis age was 67 years for husbands and 65 years for wives. A total of 214 cases (46.5 %) had digestive system malignancies. Respiratory system cancers were diagnosed in 64 husbands, of whom 20 (31.3 %) had spouses also with respiratory system cancer. Lung cancer ranked first for the females. The total number of lung cancer and commonly seen female-specific cancers (breast, ovarian, uterine, and cervical) was 127 (55.2 %). The difference in age at diagnosis between spouses was less than 10 years in 134 couples (58.3 %), while 77 (33.5 %) couples had an age difference less than 5 years. A family history of malignant tumors in first-degree relatives was documented in 48.3 % of the husbands and 48.7 % of the wives. The occurrence of cancer in both spouses of the couples studied resulted from an interaction between genetic and environmental factors. Nonhereditary factors such as diet, smoking, passive smoking, and air pollution also contributed to the development of cancers. It is recommended that when husband is diagnosed with cancer, the wife should be screened focusing on lung, breast, and gynecological cancers. If the wife was diagnosed with malignant disease, then screening for lung and digestive system cancers should be emphasized in the husband.  相似文献   

15.
Preeclampsia is a global health problem and it is the main cause of maternal and perinatal morbidity and mortality. Breastfeeding has been reported to be associated with lower postpartum blood pressure in women with gestational hypertension. However, there is no published data on the role that breastfeeding might play in preventing preeclampsia. The aim of the current study was to investigate if breastfeeding was associated with preeclampsia in parous women. A case-control study was conducted in Saad Abualila Maternity Hospital in Khartoum, Sudan, from May to December 2019. The cases (n = 116) were parous women with preeclampsia. Two consecutive healthy pregnant women served as controls for each case (n = 232). The sociodemographic, medical, and obstetric histories were gathered using a questionnaire. Breastfeeding practices and duration were assessed. A total of 98 (84.5%) women with preeclampsia and 216 (93.1%) women in the control group had breastfed their previous children. The unadjusted odds ratio (OR) of preeclampsia (no breastfeeding vs breastfeeding) was 3.55, 95% confidence interval (CI) 1.64,7.70 and p value = 0.001 based on these numbers. After adjusting for age, parity, education level, occupation, history of preeclampsia, history of miscarriage, body mass index groups the adjusted OR was 3.19, 95% CI 1.49, 6.82 (p value = 0.006). Breastfeeding might reduce the risk for preeclampsia. Further larger studies are required.  相似文献   

16.
The histological structure and morphometric and some histochemical indices of thyroid gland of maral as a subspecies of red deer at the postnatal stage of ontogenesis were studied. It was established that the gland was structurally formed by the time of the birth. C-cells are detected at 6 months of age. With age, the ratio of follicles of different sizes changed: smaller forms predominate in newborns and those 6 months old, medium and large predominate in adults and in old deer. Histological, morphometric, and histochemical data indicate to activation of the thyroid gland in the period of intensive growth for up to 6 months and a gradual decrease in activity over the next years of life. During aging, along with an increase in stromal elements, large follicles with colloid are stretched and resorption processes in the follicles are reduced.  相似文献   

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19.
Radiocarbon isotopes are increasingly being used to investigate the age and source of carbon released from peatlands. Here we use combined 14C and δ13C measurements to determine the isotopic composition of soil and soil decomposition products [dissolved organic carbon (DOC), CO2 and CH4] in a peatland–riparian–stream transect, to establish the isotopic signature and potential connectivity between carbon pools. Sampling was conducted during two time periods in 2012 to investigate processes under different temperature, hydrological and flux conditions. Isotopic differences existed in the peatland and riparian zone soil organic matter as a result of the riparian depositional formation. The peatland had a mean radiocarbon age of 551 ± 133 years BP, with age increasing with depth, and δ13C values consistent with C3 plant material as the primary source. In contrast the riparian zone had a much older radiocarbon age of 1,055 ± 107 years BP and showed no age/depth relationship; δ13C in the riparian zone was also consistent with C3 plant material. With the exception of DOC in September, soil decomposition products were predominately >100 %modern with 14C values consistent with derivation from organic matter fixed in the previous 5 years. Emissions of CO2 and CH4 from the soil surface were also modern. In contrast, CO2 and CH4 evaded from the stream surface was older (CH4: 310–537 years BP, CO2: 36 years BP to modern) and contained a more complex mix of sources combining soil organic matter and geogenic carbon. The results suggest considerable vertical transport of modern carbon to depth within the soil profile. The importance of modern recently fixed carbon and the differences between riparian and stream isotopic signatures suggests that the peatland (not the riparian zone) is the most important source of carbon to stream water.  相似文献   

20.
The propagation characteristics of symmetric surface plasmon polariton mode in a glass–metal–glass waveguide are presented. Gallium lanthanum sulfide has been taken as the glass and silver (Ag) has been used as the metal. The analysis has been done both numerically and analytically. A two-dimensional finite-difference time-domain-based simulation model has been developed in order to analyze the propagation characteristics numerically. The obtained results using numerical and analytical methods have been compared and a very good agreement has been found.  相似文献   

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