Obesity and diabetic control.
Children with diabetes mellitus are not significantly heavier than their peers, and those who are obese do not have poorer diabetic control.
Adolescent↗
Biomedical subjects
D C Savage
Publications and source records attributed to D C Savage.
Height at diagnosis in diabetes.
There was no significant difference in the heights of 66 insulin-dependent diabetic children at diagnosis when compared with age, sex and period-matched controls.
Adolescent↗
Stability of enterocytes and certain enzymatic activities in suspensions of cells from the villous tip to the crypt of Lieberkühn of the mouse small intestine.
A series of studies in this laboratory have focused on how an indigenous microbiota influences the activities of alkaline phosphatase, phosphodiesterase I, and thymidine kinase in the enterocytes of the upper small intestine of mice. To draw conclusions about the role of the microflora in determining levels of enzymatic activity, we found it necessary to develop a procedure by which cell suspensions could be obtained containing enterocytes isolated sequentially from the villous tip to the crypt of Lieberkühn. The procedure was modified from the one developed for rats by Weiser (J. Biol. Chem. 248:2536-2541, 1973), involved a minimum number of interfering factors (e.g., proteolytic enzymes and mechanical agitation), and worked reproducibly for mice. During development of the procedure, some variables affecting the assays of the enzymes known to be present in enterocytes were also explored. Rods to which were tied everted segments of gut were incubated in a series of tubes containing a solution of EDTA the concentration of which was changed from 1.5 to 5.0 mM, thus giving a greater yield of enterocytes at every step. The cells incubating in the chelating solution were most stable when 0.23 M sucrose was included in the EDTA solutions. Success in assaying enzymatic activities in the cell suspensions depended on (i) how the cells were isolated, (ii) the assay procedure for thymidine kinase, and (iii) whether cellular suspensions or extracts were assayed.
Alkaline Phosphatase↗
Influence of indigenous microbiota on activities of alkaline phosphatase, phosphodiesterase I, and thymidine kinase in mouse enterocytes.
An indigenous microflora introduced into the gastrointestinal tracts of animals in a population of germfree mice affected in different ways three enzymes in small bowel enterocytes. Cells were obtained by techniques designed for sequentially removing enterocytes from the tip of the villus to the crypts of Lieberkühn. The specific activity of alkaline phosphatase, a component of the enterocyte microvillous membrane, did not differ in cells isolated from germfree mice and from those associated with a microflora, while that of phosphodiesterase I, also a part of the microvillous membrane, was approximately 1.5-fold greater in the suspensions from all levels of the villi in germfree mice than in those from the associated animals. By contrast, the specific activity of thymidine kinase, a cytosol enzyme, in suspensions in which the cells were isolated from the lower portion of the villi and crypts was about one-half as great in cells from germfree mice as in those from the same regions of animals with a microbiota. These results support the hypothesis that activities of certain enzymes involved in metabolism, uptake, and incorporation by enterocytes of components of dietary nuclei acids are influenced by a microflora.
Alkaline Phosphatase↗
Genetic transformation in Lactobacillus sp. strain 100-33 of the capacity to colonize the nonsecreting gastric epithelium in mice.
Lactobacillus isolates able to colonize the surfaces of the nonsecreting epithelia in the stomachs of monoassociated ex-germfree mice were derived from Lactobacillus acidophilus 100-33. Strain 100-33 was originally isolated from pig feces and is unable to colonize the murine gastric epithelium. In experiments involving attempts genetically to transform the capacity to colonize the epithelium, cells of strain 100-33 were treated with muralytic enzymes and mixed with polyethylene glycol and genomic or plasmid DNA extracted from Lactobacillus fermentum RI. Strain RI was originally isolated from a conventional mouse and has the capacity to colonize the nonsecreting gastric epithelium. The mixtures containing cells, polyethylene glycol, and DNA were plated on a regeneration medium. After overnight incubation, the cells were washed from the plates and introduced by gastric gavage into germfree mice. Only mice that received regenerated 100-33 cells previously mixed with genomic DNA from strain RI had layers of gram-positive bacteria on the keratinized epithelia of their stomachs. Six isolates cultured from the washed gastric tissues of these animals were characterized. When a culture of each or a pool of cultures of the six were orally administered to germfree mice, layers of gram-positive bacterial cells were visible on the keratinized gastric epithelia of the animals within 1 to 3 weeks. Cells of all six, but not of strain 100-33, reacted with antibody made in rabbits to L. fermentum RI cells, as determined by an enzyme-linked immunosorbent assay. Nevertheless, all six had fermentation profiles identical to that of strain 100-33.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Degradation of DNA in cells and extracts of the obligately anaerobic bacterium Roseburia cecicola upon exposure to air.
High-molecular-weight chromosomal DNA from Roseburia cecicola, an oxygen-intolerant anaerobe, could be isolated only when the bacterial cells were kept under anaerobic conditions up to the time of cell lysis. When the cells were exposed to oxygen before lysis, the chromosomal DNA degraded. Likewise, linear but not covalently closed circular DNAs degraded in cell extracts of the organism that were exposed to atmospheres containing O2 but not in extracts that were maintained in a reduced state. Covalently closed circular DNAs were nicked but not degraded in the oxidized extracts.
Anaerobiosis↗
Cloning, nucleotide sequence, and taxonomic implications of the flagellin gene of Roseburia cecicola.
The gene coding for the flagellin protein of Roseburia cecicola, an oxygen-intolerant, gram-negative, anaerobic bacterium indigenous to the murine cecum, has been cloned and sequenced. NH2-terminal amino acid sequence data from the flagellin protein were used as a basis for the synthesis of two mixed-sequence deoxyoligonucleotides. The oligonucleotides were used to identify and clone the flagellin structural gene. DNA sequence analysis of M13mp8 and mp9 subclones revealed a protein with a length of 293 amino acids and a molecular weight of 31,370. Comparisons with the sequences of flagellins of other species revealed conserved regions and suggested that although R. cecicola has structural characteristics of a gram-negative bacterium, it may be most closely related to the gram-positive bacteria.
Amino Acid Sequence↗
Serum thyroxine and thyroid stimulating hormone concentrations after treatment of congenital hypothyroidism.
Serum thyroid stimulating hormone and thyroxine concentrations were monitored in 42 infants who had been treated for congenital hypothyroidism. Serum thyroid stimulating hormone concentrations were raised in 22 of the infants (52%) at 2 to 4 months, in 16 (38%) at 5 to 11 months, in 14 (33%) at 12 to 18 months, and in eight (19%) at 2 to 4 years. Serum thyroxine and the dose of L-thyroxine/kg/body weight were significantly lower in those infants with raised thyroid stimulating hormone concentrations. Thyroid stimulating hormone was appropriately suppressed when the dose of L-thyroxine was increased, and only one child had delayed maturation of the hypothalamic/pituitary/thyroid axis. We believe it is the infant's rapid gain in weight in the first two years of life that necessitates this decrease in the dose of L-thyroxine/kg body weight and recommend that the treatment of this age group is reviewed every two to three months.
Aging↗
Growth hormone, suspected gonadotrophin deficiency, and ring 18 chromosome.
A boy with a ring 18 chromosome karyotype was referred because of short stature; he had growth hormone deficiency and possible hypogonadotrophic hypogonadism. Many children with major chromosomal abnormalities are short, but this case emphasises the need to consider growth hormone deficiency in addition.
Child, Preschool↗
Microorganisms associated with epithelial surfaces and stability of the indigenous gastrointestinal microflora.
Indigenous microorganisms of many genera and species associate with mucosal epithelia in the gastrointestinal tracts of animals and humans. These mechanisms may involve a high degree of specificity for host and surface habitat. They may include a capacity of the microorganisms to adhere to the membranes of substratum epithelial cells, to colonize and utilize as a source of nutrients the mucus overlying epithelial cells, and to be motile and attracted into the mucous layer by chemotaxis. The microbes must be able as well to thrive in the nutritional and environmental conditions prevailing on the epithelial surfaces. Microbial communities associated with epithelial surfaces are critical for maintaining a microflora in areas of the tract (i.e., stomach, small intestine) where the lumenal content moves at a rate exceeding the maximum rates at which indigenous microorganisms can multiply. Such communities even may be important in areas (i.e., the cecum and colon) where the content moves at rates below those at which the microbes can multiply. In such areas, microorganisms colonizing mucus on the epithelium and in the crypts of Lieberkuhn may provide a stable inoculum for the lumenal content which may be altered in composition in times of dietary change. Microorganisms associated with gastric and intestinal surfaces undoubtedly serve in a major way to stabilize the composition of the indigenous gastrointestinal microflora. At the molecular level, however, little is known about the mechanisms stabilizing the composition or the biochemical and genetic activities of the microflora. Such mechanisms are important subjects for research in the future.
Animals↗
Lactobacilli as effectors of host functions: no influence on the activities of enzymes in enterocytes of mice.
Preparations of lactobacilli are often used as dietary supplements to improve the growth and efficiency in utilizing food of animals of commercial value. We tested in an experimental model whether the effects of lactobacilli on growth of and food utilization by animals may be due to alteration of the activities of absorptive enzymes in the small bowel. Germfree mice housed in isolators under tightly controlled conditions were monoassociated with one of four strains of indigenous Lactobacillus spp. From 1 to 5 weeks later, the activity of alkaline phosphatase was assayed in homogenates of segments of the upper small intestines of the associated animals and of matched germfree controls. The specific activity of the enzyme was the same in the mice in the two groups. In other experiments, epithelial cells were isolated from the upper small intestines of mice associated with eight Lactobacillus strains (octa-associated) and from those of matched germfree mice and assayed for alkaline phosphatase, phosphodiesterase, and thymidine kinase activities. The epithelial cells were harvested sequentially from the tips of the villi toward the crypts of Lieberkühn of the intestines. In all preparations, mice of both types yielded an equivalent mass (wet weight) of cells. The protein content of the cells reflected the mass. The activities of the microvillous membrane enzymes alkaline phosphatase and phosphodiesterase and the cytosol enzyme thymidine kinase were the same whether or not the animals contained the bacteria. Therefore, any effects on animal growth and food utilization observed when lactobacilli are used as dietary supplements may not be due to a direct alteration by the bacteria of the absorptive enzymes of the host animal.(ABSTRACT TRUNCATED AT 250 WORDS)
Alkaline Phosphatase↗
Mitochondrial DNA in Candida pintolopesii, a yeast indigenous to the surface of the secreting epithelium of the murine stomach.
Candida pintolopesii 108-1 is an indigenous yeast which colonizes the surface of the secreting gastric mucosa of mice. We have been exploring the aerobic respiratory capacities of this organism in reference to its capacity to colonize the stomach surface, an environment that could contain little oxygen for microbial growth. In this paper, we report mitochondrial DNA and membranes in cells of a strain of this yeast isolated from the gastric epithelium of a mouse and compare the findings with those made by other investigators in studies of Saccharomyces cerevisiae. Putative mitochondrial DNA was isolated from crude lysates of C. pintolopesii and S. cerevisiae as fluorescing bands in CsCl gradients containing 4',6-diamidino-2-phenylindole. The DNA from C. pintolopesii hybridized with a 32P-labeled DNA probe for the 21S rRNA gene encoded by mitochondrial DNA in S. cerevisiae. Postvital cell staining with 4',6-diamidino-2-phenylindole and rhodamine 123 revealed mitochondrial DNA and membranes, respectively, in the cytoplasm of intact C. pintolopesii cells. The staining patterns were generally similar to those reported for S. cerevisiae. Finally, structures similar to those reported to be mitochondria in electron micrographs of S. cerevisiae were seen in preparations of C. pintolopesii cells examined by transmission electron microscopy. These data confirm findings from studies of its respiratory capacity published earlier that a strain of C. pintolopesii isolated directly from its native habitat has functional mitochondria.
Aerobiosis↗
Influences of conjugal genetic transfer functions of colicin V plasmids on adhesion of Escherichia coli to murine intestinal tissue.
Cells of strains of Escherichia coli K-12 291 bearing one of three colicin V plasmids, pF54, pH247, or pF70, were tested in comparison with cells of strain 291 for their ability to adhere to murine intestinal tissue in vitro. The plasmids were either repressed or derepressed in conjugal genetic transfer functions. The strains bearing pF54 and pH247 repressed in transfer functions (pColVF54 luminal diameter r and pColVH247 luminal diameter r) adhered in higher numbers to the murine tissue than did the host strain lacking the plasmid or the strains containing the plasmids with active transfer functions (pColVF54drd and pColVH247drd). The number of cells (CFU) of strain 291(pColVF54 luminal diameter r) adherent to the tissue was related directly to the time of incubation (up to 30 min) and to the number of cells (CFU) to which the tissues were exposed. As indicated by tests for sensitivity to F factor (F)-pilus-specific bacteriophages, the cells of strains bearing the plasmids derepressed for conjugal functions had F pili on their surfaces, while such structures were missing from cells of the parental strain (291) and the strains containing the plasmids in repressed form. This finding was supported by transmission electron microscopy of cells of strain 291, 291(pColVF54 luminal diameter r), and 291(pColVF54drd). F pili could be seen on cells of the latter strain but not on those of the parental strain or the strain bearing pColVF54 luminal diameter r. Pili other than F pili were not seen on cells of the strains bearing pF54 in either form. Strains 291(pColVF70drd) and 291(pColVF70 luminal diameter r) adhered to the tissues in numbers comparable to those of strain 291. Nevertheless, these findings are further evidence that for certain colicin V plasmids (A. M. Nilius and D. C. Savage, Infect. Immun. 43:947-953, 1984), conjugal genetic transfer functions influence properties that may be important in the pathogenesis of invasive E. coli strains.
Animals↗
Accuracy of home blood glucose monitoring by children.
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Adolescent↗
Genetic transformation of rifampicin resistance in Lactobacillus acidophilus.
Lactobacillus acidophilus strain 100-33, originally isolated from swine faeces, was transformed to rifampicin resistance with DNA from spontaneous rifampicin-resistant mutants derived from it. Cells of the recipient strain were treated with lysozyme and mutanolysin, mixed with donor DNA and polyethylene glycol and grown on a regeneration medium overnight. After 48 h incubation, the numbers of rifampicin-resistant cells in the populations of regenerated cells were estimated from numbers of colonies. Efficiency of the lysozyme/mutanolysin treatment (the ratio of the number of osmotically fragile cells after the enzyme treatment to the initial cell number) was about 99%. The regeneration frequency of the enzyme-treated cells varied from 5 to 67%. The transformation frequency varied from about 0.2 X 10(-8) to 8.0 X 10(-8) transformants per regenerated cell per microgram DNA. To our knowledge, this method for genetic transformation is the first to be reported for a Lactobacillus strain.
DNA, Bacterial↗
Lipoteichoic acids in Lactobacillus strains that colonize the mouse gastric epithelium.
Extracts of cells of 22 strains of Lactobacillus species, and of fluids from cultures in a defined medium of two of the strains, were assayed by hemagglutination inhibition for lipoteichoic acids. A total of 10 of the preparations gave positive tests for the acids, including those from eight strains known to adhere to the keratinized squamous epithelium of the mouse stomach. These findings are consistent with an hypothesis that lactobacilli colonize the epithelial surface via adhesive interaction with the keratinized cells mediated by macromolecular complexes containing lipoteichoic acids.
Animals↗
Gastrointestinal microflora in mammalian nutrition.
A mammal is a complex organism consisting of eukaryotic animal cells and eukaryotic and prokaryotic microbial cells. Most of the microorganisms reside in communities in the gastrointestinal tract. These gastrointestinal microfloras are known to serve nutritional functions in ruminants, pseudoruminants, and monogastric mammals with only modest or no foregut fermentations but with extensive hindgut fermentations in blind cecal pouches. In adult animals, the microflora hydrolyzes exogenous (dietary) and endogenous polymers, and provides the adult with all or at least a significant proportion of its carbon, energy, vitamins, and macromolecular building blocks. The flora also functions as a conservator of nitrogen that would otherwise be excreted as urea. In exchange, the flora competes directly with the host tissues for nutrients ingested in the diet, and also competes indirectly by somewhat repressing the absorptive capacities of the animal tissues. When the synergism is in balance, the animal tissues and the microflora operate in harmony for the health and nutritional welfare of the host as a whole. The system may be unbalanced by antibacterial drugs that destroy the microflora and by diseases of the animal tissues that destroy the controls regulating where indigenous communities localize in the tract, their microbial composition, and their biochemical activities. At such times, the nutrition of the animal tissues can be adversely affected to the extreme. Humans living in developed and developing countries have extensive microfloras in their hindguts. Humans living in developing countries may also have extensive microfloras in their small bowels. Those floras may function in nutrition of the animal tissues of man much the same as do floras in similar locations in the gastrointestinal tracts of mammals other than man. However, animals of some species other than human gain much of the nutritional benefit from their microflora through the practice of coprophagy. Since adult humans do not normally practice coprophagy, any nutritional benefit from the microflora depends upon the capacity of the bowel mucosa, principally that of the large bowel, to absorb bacterial products, e.g. short-chain volatile fatty acids. Such absorption undoubtedly occurs, but is surely not a major source of carbon and energy for the animal tissues of man.
Anaerobiosis↗
The effects of a dietary antimicrobial on the biological half-life of chenodeoxycholic acid and plasma bile acid concentration patterns in the young pig.
Carbodox (CX), an antimicrobial agent, was fed at 0 or 58 ppm in a 19.5% crude protein corn-soybean metal diet to young pigs (12 to 15 kg). Radiolabeled chenodeoxycholic acid (CDC) was infused into the hepatic portal vein; after each of the subsequent six meals, blood samples were collected from the anterior vena cava (VC) and the hepatic portal (HP) veins. For the first 5 min after CDC infusion, the level of radioactivity in the CX pigs was significantly lower in the HP plasma and the slopes of the two curves of the plasma activity for the first hours were significantly different. The plasma bile acid concentrations (as measured by radioactivity) were significantly higher in the CX-treated animals following all meals. The biological half-life of CDC was 6.4 d in the controls and 5.7 d in the CX pigs. The increased rate of excretion was significant. These data indicate that bile acid metabolism in the young pig was significantly affected by feeding a subtherapeutic level of the antimicrobial CX.
Animals↗