Intestinal microflora of the newborn rat as related to mammary, faecal, and vaginal Staphylococci strains isolated from the dam

1989 ◽  
Vol 35 (11) ◽  
pp. 989-993 ◽  
Author(s):  
A. Brunel ◽  
P. Gouet
Keyword(s):  
Numerical Taxonomy ◽  
Intestinal Microflora ◽  
Relative Importance ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Degree Of Similarity

To determine the relative importance of maternal microflora (faeces, vagina, and teats) in the contamination of newborn rats, strains of staphylococci from six different families (dam + litter) were isolated. These strains were identified, and by means of numerical profiles analyzed for their degree of similarity for each litter and (or) biotope. The staphylococci strains found in the gut of the newborn rat originated first from the teats and thereafter from the faeces. Concomitant observation of some identical strains, however, suggested a certain degree of similarity between these two maternal biotopes in this animal.Key words: intestinal microflora, newborn, dam, staphylococci, numerical taxonomy.

Oxygen toxicity in newborn rats: the adverse effects of undernutrition

1982 ◽  
Vol 53 (5) ◽  
pp. 1248-1255 ◽  
Author(s):  
L. Frank ◽  
E. Groseclose
Keyword(s):  
Dna Content ◽  
Oxygen Toxicity ◽  
Lung Damage ◽  
Newborn Rats ◽  
Inhibitory Effects ◽  
Similar Extent ◽  
Newborn Rat ◽  
Lung Maturation ◽  
Rat Pups ◽  
Growth Inhibitory

Undernutrition was found to compromise the tolerance of newborn rat pups to hyperoxia (greater than 95% O2 for 7 days). Survival rate for the normally nourished pups (11 pups/dam) was 56 of 77 (73%) but only 47 of 108 (44%) for the undernourished (18 pups/dam) group (P less than 0.005). Body growth, lung growth, and lung DNA content were significantly reduced by undernutrition. Hyperoxia inhibited these same parameters in both groups of pups. The growth inhibitory effects of O2 and undernutrition were additive, with an especially marked depression of lung DNA content (decreases 65%). Lung maturation was also markedly inhibited by O2 but to a similar extent in both nutrition groups. Despite the disparity in their O2 tolerance, 18/litter and 11/litter pups in O2 responded with equivalent increases in lung antioxidant enzymes. We suggest that the additive depressive effects of neonatal undernutrition and hyperoxia on lung DNA may compromise repair of ongoing O2-induced lung damage and help account for the compromised O2-tolerance we consistently observed even in the presence of significantly elevated antioxidant enzyme defenses.

THE EFFECTS OF CALCITONIN AND PARATHORMONE ON PLASMA MAGNESIUM LEVELS BEFORE AND AFTER BIRTH IN THE RAT

1974 ◽  
Vol 61 (1) ◽  
pp. 1-13 ◽  
Author(s):  
J. M. GAREL ◽  
J. P. BARLET
Keyword(s):  
Parathyroid Hormone ◽  
Salmon Calcitonin ◽  
Magnesium Level ◽  
Plasma Calcium ◽  
Parathyroid Glands ◽  
Small Decrease ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Before And After ◽  
Plasma Magnesium

SUMMARY Plasma magnesium levels measured in rats from 16·5 to 21·5 days of gestation and during the first week after birth proved to be invariably higher in the foetus than in the mother. The highest level observed was in the 16·5-day-old foetus. A small decrease occurred between 16·5 and 17·5 days of gestation; thereafter the plasma magnesium level did not change until 19·5 days and then decreased between 19·5 and 21·5 days. After birth an increase in plasma magnesium occurred with suckling but then remained constant during the first week of life. Parathyroid hormone (0·25 USP unit/g) injected into 21·5-day-old foetuses had no effect on plasma magnesium levels from 0·5 to 24 h after injection. This dose was found to be very potent in raising plasma calcium values 4 h after injection. In the 3-day-old newborn rat this dose was similarly ineffective. Removal of the foetal parathyroid glands by decapitation at 17·5 days of gestation was followed by a decrease in plasma magnesium at 21·5 days of gestation. Parathyroid hormone (0·25 USP unit/g) injected into decapitated foetuses did not change the level of magnesium in the plasma. Salmon calcitonin (S-CT) at two doses (0·4 and 4 ng/g) produced no effect on plasma magnesium concentrations in 3-day-old newborn rats 3 h after injection; whereas at both doses, marked diminutions in plasma calcium and phosphate concentrations were observed. After injection of 40 ng S-CT/g, plasma magnesium decreased in 3-day-old newborn rats 3 h after injection. This dose was found to decrease plasma magnesium in the 19·5-day-old foetus and in the 20·5-day-old foetus. Before 19·5 days of gestation no effect was observed.

GLUCAGON RELEASE FROM THE PANCREAS OF THE NEWBORN RAT

1972 ◽  
Vol 54 (3) ◽  
pp. 493-504 ◽  
Author(s):  
J. C. EDWARDS ◽  
K. ASPLUND ◽  
G. LUNDQVIST
Keyword(s):  
Inhibitory Action ◽  
Octanoic Acid ◽  
Ketone Bodies ◽  
Solid Phase ◽  
Glucagon Release ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Stimulatory Action ◽  
Rat Pancreas ◽  
Solid Phase Radioimmunoassay

SUMMARY A solid phase radioimmunoassay for glucagon was specially modified in order to overcome the problems involved in the measurement of glucagon release from incubated pieces of pancreas. The modified immunoassay procedure was used to study glucagon release from pieces of pancreas taken from newborn rats aged from 1 to 20 days. The glucagon content of rat pancreas was also measured during this period. It was found that glucagon release from rat pancreas was stimulated by arginine and inhibited by octanoic acid at 1 and 2 days of age. However, glucagon release at 3 days of age was low, and between 3 and 7 days of age glucagon release could not be inhibited by octanoic acid or stimulated by arginine. At 10 and 20 days of age, the stimulatory action of arginine and the inhibitory action of octanoic acid were again noted. Glucagon release, measured at several ages, was not significantly affected by changes in glucose concentration. The glucagon content of the rat pancreas rose to a maximum at 5 days of age and then decreased gradually over a period of 90 days. It is suggested that the low rate of glucagon release between 3 and 7 days of age may be a result of the high levels of blood fatty acids and ketone bodies found in the rat during this period.

THE BIOASSAY OF THYROTROPHIC HORMONE ON NEWBORN RATS

1956 ◽  
Vol 13 (4) ◽  
pp. 412-416 ◽  
Author(s):  
JEAN M. REISS ◽  
AUDREY F. WYATT
Keyword(s):  
New Method ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Reasonable Degree ◽  
Thyrotrophic Hormone ◽  
Test Objects

SUMMARY A new method for the bioassay of thyrotrophic hormone is described. Newborn rat litter-mates are used as test objects. The method is easily carried out and achieves a reasonable degree of precision with fewer animals than used in other methods.

RESPONSIVENESS OF THE OVARY TO GONADOTROPHINS IN PRE- AND PERINATAL LIFE: OESTROGEN SECRETION IN TISSUE AND ORGAN CULTURES

1975 ◽  
Vol 65 (2) ◽  
pp. 219-223 ◽  
Author(s):  
S. E. LEVINA ◽  
A. GYÉVAI ◽  
E. HORVÁTH
Keyword(s):  
Tissue Culture ◽  
Culture Medium ◽  
Tissue Cultures ◽  
Newborn Rats ◽  
Organ Cultures ◽  
Newborn Rat

SUMMARY Secretion of oestrogen by the ovaries of foetal (15–19 days of gestation) and newborn rats in organ and tissue culture was not detectable by fluorometry when the ovary was taken from foetuses before folliculogenesis had occurred. In organ cultures of ovaries, the time of folliculogenesis corresponded with the normal timing of folliculogenesis in vivo. In tissue cultures the process of formation of follicles was delayed. Oestrogens were present in the medium when folliculogenesis was fully established in the cultured foetal ovaries. Secretion began spontaneously and did not depend on the addition of gonadotrophins to the medium. The addition of gonadotrophins to the culture medium did not affect the level of oestrogen secreted by the foetal and newborn rat ovaries during the period of incubation (2–3 weeks).

Metabolism of Carbon14-Labeled Pyruvate by the Newborn Rat

1955 ◽  
Vol 184 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Ruth Kimmelstiel ◽  
Claude A. Villee
Keyword(s):  
Glycogen Content ◽  
Fold Increase ◽  
Liver Glycogen ◽  
Total Lipids ◽  
Newborn Rats ◽  
Anaerobic Conditions ◽  
Newborn Rat ◽  
Carbon 14 ◽  
Liver Glycogen Content ◽  
Old Rats

Pyruvate labeled with carbon-14 was administered intraperitoneally to newborn rats which were subsequently subjected to periods of aerobiosis or anaerobiosis. Expired air was analyzed for carbon dioxide, and blood, liver and carcass were analyzed for pyruvate, lactate, glycogen and total lipids. Small quantities of CO2 were produced anaerobically but this was not derived from the direct decarboxylation of pyruvate. Anaerobiosis resulted in a five-fold increase in blood lactate. The liver glycogen content of 10–24-hr-old rats treated anaerobically was only 10% of that of those kept in oxygen. The premature and newborn rats were apparently unable to mobilize glycogen in response to anoxia. The amounts of liver or carcass lipids were not significantly different after aerobic or anaerobic conditions. Lipogenesis occurred anaerobically at a rate not greatly different from that observed in aerobic conditions. In contrast, the data suggest that the utilization of lipids is reduced by anaerobiosis. No gross changes were found that could entirely explain the ability of neonates to survive prolonged oxygen deprivation but part, at least, of the energy for survival was provided by accelerated glycolysis.

scholarly journals Erythropoietin production in response to anemia or hypoxia in the newborn rat

Blood ◽  
1982 ◽  
Vol 60 (4) ◽  
pp. 984-988
Author(s):  
J Caro ◽  
AJ Erslev ◽  
R Silver ◽  
O Miller ◽  
G Birgegard
Keyword(s):  
Neonatal Period ◽  
Oxygen Affinity ◽  
Dissociation Curve ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Adult Rat ◽  
Erythropoietin Production ◽  
Hemoglobin Oxygen Affinity ◽  
Tissue Homogenates ◽  
Erythropoietin Level

Erythropoietin production in response to hypoxic-hypoxia is markedly reduced in the newborn when compared to the adult rat. This response improves steadily with age and reaches adult values at about 4 wk. When animals of the same age are stimulated with anemic-hypoxia, considerably higher levels of erythropoietin are found. The erythropoietin level is proportional to the degree of anemia and independent of the age of the animal. Extraction of erythropoietin from tissue homogenates revealed a parallelism between the plasma and kidney erythropoietin content, while no erythropoietin could be extracted from liver tissue at any age. The lack of response to hypoxia in the newborn appears to be related to the high hemoglobin oxygen affinity during the neonatal period, which facilitates oxygen loading. Newborn rats have a very low intraerythrocytic concentration of 2–3 DPG and a marked shift to the left in the oxygen hemoglobin dissociation curve that slowly increases to adult values at 4 wk of age. The response to anemia on the other hand, appears to be normal and not affected by age or by hemoglobin oxygen affinity. These studies suggest that the newborn rat, when properly stimulated, is able to produce normal amounts of erythropoietin, most likely renal in origin.

Differentiation of liver peroxisomes in the foetal and newborn rat. Cytochemistry of catalase and D-aminoacid oxidase

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 151-163
Author(s):  
S. Stefanini ◽  
M. G. Farrace ◽  
M. P. Cerù Argento
Keyword(s):  
Rat Liver ◽  
Gradual Increase ◽  
Individual Cell ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Foetal Development ◽  
Tissue Area ◽  
Foetal Rat ◽  
Parenchymal Cells ◽  
Liver Peroxisomes

Organules containing cytochemically detectable amounts of catalase and D-aminoacid oxidase activities are observed between the 14th and 21st day of development in the parenchymal cells of the foetal rat liver and in the liver of newborn rats. As early as 14 to 15 days, a limited number of small microperoxisomes, scattered in the cytoplasm of very few hepatocytes, can be found. These are roundish shaped, have a granulous matrix and contain very low, hardly detectable levels of the above mentioned enzymes. In later development both the size and the enzymatic content of the organules gradually increase, approaching adult levels at the end of foetal development. Starting from the 18th to 19th day of intrauterine life nucleoids can be seen in many peroxisomes. The morphological and biochemical maturation from microperoxisomes to peroxisomes is accompanied by a gradual increase in the number of stainable organules, both per individual cell and per tissue area.

Effects of hypoxia and hypercapnia on the Hering-Breuer reflex of the conscious newborn rat

1995 ◽  
Vol 78 (1) ◽  
pp. 5-11 ◽  
Author(s):  
T. Matsuoka ◽  
J. P. Mortola
Keyword(s):  
Lung Volume ◽  
Ventilatory Response ◽  
Developmental Differences ◽  
Similar Amount ◽  
Newborn Rats ◽  
Newborn Rat ◽  
Early Postnatal Development ◽  
Expiratory Time ◽  
Control Value ◽  
Inhibitory Ratio

We asked whether hypoxia and hypercapnia, singly or combined, affect the lung volume-dependent ventilatory inhibition [Hering-Breuer (HB) reflex] in newborn rats. Conscious rats 2, 5, and 8 days old were breathing in a flow plethysmograph. Mean lung volume was increased by applying a negative body surface pressure of 6 or 12 cmH2O. HB reflex was quantified as the inhibitory ratio (IR) of the apnea during the inflation expiratory time (TEinfl) to the control expiratory time (TEc), i.e., IR = TEinfl/TEc. In normoxia-normocapnia (control), IR with 6 cmH2O was approximately 8–12 at all ages and approximately doubled with inflation at 12 cmH2O. In hypoxia (HPX; 10% O2) or hypercapnia (HPCN; 3% CO2), IR decreased at 8 days, whereas it did not differ from the control value at 2 and 5 days. In HPX + HPCN, IR decreased at all ages. In HPX (at both 6- and 12-cmH2O inflations), in HPCN (6 cmH2O), or in HPX + HPCN (6 and 12 cmH2O), IR decreased significantly more at 8 days than at 2 days. Metabolic rate, simultaneously measured, decreased during HPX or HPX + HPCN by a similar amount at all ages. The ventilatory response to HPX or to HPCN was significantly more pronounced at 8 days than at 2 days. We conclude that, during the early postnatal development of the rat, HPX or HPCN, singly or combined, reduces the HB reflex inhibition in the oldest pups, with minimal or no effects in the youngest. These developmental differences cannot be explained by differences in metabolic drive on ventilation but are contributed to by differences in chemosensitivity.

The Stability of Benefit Segments

1978 ◽  
Vol 15 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Roger J. Calantone ◽  
Alan G. Sawyer
Keyword(s):  
Relative Importance ◽  
Product Attributes ◽  
Group Designation ◽  
Time Period ◽  
Managerial Implications ◽  
Individual Household ◽  
The Stability ◽  
High Degree ◽  
Degree Of Similarity ◽  
Previous Group

An important and neglected question for marketing managers is whether identified market segments remain similar over time in terms of distinguishing characteristics and size. Benefit segments based on the relative importance of product attributes were shown to be internally consistent between split halves for a given time period. Two years later, a comparison of the same households segmented in terms of sought benefits revealed a high degree of similarity in product attributes considered important and segment size. However, analysis on an individual household basis showed that a household was very likely to be classified in a segment other than its previous group designation. Managerial implications of the research are discussed.

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