摘要:

A mathematical model of the Base Excess curve of blood was developed and then programmed into a digital computer coupled to an automatic plotter. Values for serum albumin, globulin and mean corpuscular hemoglobin concentrations were fed to the computer and theoretical Base Excess curves were generated. Normal values gave a curve which closely approximated the experimentally derived curve of SIGGAARD-ANDERSEN. When values characterizing hypoproteinemia, hypochromia or tris-(hydroxymethyl)-aminomethane buffering were introduced, Base Excess curves were produced which varied, often markedly, from the traditional curve.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

A satisfactory technique for the continual infusion of solutions into the intestinal tract of the small animal was developed. Using this technique, dilute solutions of lactic acid were infused into the rat and their effect on fat absorption and mucosal structure assessed. Thirty-five rats were studied in five groups, infused with either ion-free water or lactic acid (2.0 g/100 ml, 2.5g/100 ml, 3.0 g/100 ml, 3.5 g/100 ml) for 10 days. Fecal fat excretion measured as a percentage of ingested fat was increased significantly in rats infused with acid in a concentration of 3.0 g/100 ml (7.2 ± 2.1) and 2.5 g/100 ml (6.5 ± 2.1) compared to the water-infused group (2.9 ± 1.9) or those infused with lactic acid 2.0g/100 ml (2.2 ± 0.9). Six rats infused with lactic acid 3.5 g/100 ml died within 72 hours of a perforated intestine and the two remaining ones were killed prematurely for histological study.Histological abnormalities were confined to the small intestine. Mucosal structure was normal in both the water-infused group and those receiving lactic acid 2.0g/100 ml. Shortening of villi occurred at the site of infusion in both the groups infused with lactic acid 2.5 g/100 ml and 3.0 g/100 ml. Fusiform processes of epithelial cells were observed extending on narrow pedicles from the tips of some of the shortened villi. Gross derangement of villous structure was observed in two rats killed after 48 hours on the most concentrated acid (3.5 g/100 ml).It is probable that the abnormalities in fat absorption and mucosal structure were a direct effect of the infusion with lactic acid. The mechanism behind the development of steatorrhea can only be the subject of speculation. The histological observations suggest that the lesions produced in the mucosa were associated with disordered turnover of the surface epithelial cells.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

Maternal respiratory alkalosis from hyperventilation before delivery has been associated with depression and acidosis of some newborn infants. In thesein uterostudies of 6 primate fetuses, acute maternal hyperventilation significantly increased both the maternal and the fetal pH and thus increased the oxygen affinities of maternal and fetal hemoglobins. In comparison with the control period, during hyperventilation 71 % more CO2was removed from the uterus and its contents. The average O2consumption by the uterus and placenta, 3.4 ml/min, and the fetus, 2.1 ml/min was unchanged during hyperventilation. Mean pO2in the umbilical vein during hyperventilation fell to 24.8 mm Hg and saturation to 65%, and umbilical blood flow increased from 40 to 45 ml/min. Average uterine blood flow decreased slightly during hyperventilation. During these same comparison periods, neither maternal and fetal heart rate nor arterial venous pressures changed significantly. Thus, although pO2and saturation in the umbilical and uterine venous blood decreased, the amount of oxygen delivered to each fetus remained relatively constant due in part to an increase in umbilical blood flow and to shifts in the oxygen dissociation curves of fetal and adult hemoglobins.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

Previous studies by us have shown that an increase in the lung surface-active phospholipids is closely related to fetal maturation. The present experiments were performed to determine the relation between fetal maturation and the rate of incorporation of several labelled precursors into phospholipids by lung slices from fetal and newborn lambs.Lung and liver specimens were removed from seven fetal lambs of various gestational ages, nine newborn lambs ranging in age from 1 day to 6 months and from five of the mothers and one non-pregnant ewe. About 500 mg of tissue, mixed with a radioactive precursor in Krebs Ringer Bicarbonate Buffer, was incubated at 38° for three hours. The incorporation of 14C from the various tagged precursors was determined by means of a radiochromatogram scanner after thin layer chromato-graphy.Results showed an increase in the rate of incorporation of14C labelled choline, palmitate and glucose into lung phospholipids, especially lecithin, as the fetus matured. Palmitate incorporation into lecithin was studied; after birth, it was found that the liver was less active than the lung until one month of age, but exceeded the lung in this function by three months after birth. These findings apparently reflect a difference in the development of the enzyme systems involved in phospholipid metabolism in both organs during maturation. From these studies, it is apparent that the lung of the maturing fetus is uniquely prepared for the synthesis of phospholipid, particularly of lecithin. The major significance of the higher rate of biosynthesis of lung lecithin in the fetus near term and newborn may be closely related to active synthesis of surfactant in the lung.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

Tryptophan oxidation was evaluated in 6 institutionalized phenylketonuric subjects (age range 5–13 years) by measuring the urinary excretion of oxidation metabolites following administration of L-tryptophan loads by mouth. Observations were made when subjects were on a general diet, a low-phenylalanine diet and a low-phenylalanine diet containing added L-phenylalanine. At some time during each dietary regime, the subjects also received tryptophan by mouth, 100 mg/kg body weight. Measurement was made in urine of: 1. 3-hydroxykynurenine; 2. kynurenine; 3. acetyl kynurenine; 4.3-hydroxyanthranilic acid; 5. xanthurenic acid; 6. kynurenic acid; 7. anthranilic acid; 8.3-indole-acetic acid; 9. o-hydroxyphenylacetic acid; and 10. phenylpyruvic acid. Excretion of tryptophan-kynurenine metabolites (products 1–9) amounted to 3.78 μmoles/kg/24 h and was similar to that of control subjects while on all diets. With tryptophan loading on normal diets, excretion of metabolic products was lower than for control subjects. With tryptophan loading on low-phenylalanine diets, the excretion of tryptophan metabolites was 2–3 times higher than the mean value of 22.7 μmoles/kg/ 24 h observed in normal subjects. The response to loading when the diet contained added phenylalanine was variable, since two patients excreted normal amounts of metabolites and three excreted amounts several times greater than the controls. Excretion of indole and 3-indoleacetic acid was abnormally elevated with and without tryptophan loading on normal diets and when phenylalanine was added to the low-phenylalanine diets. Values in μmoles/kg/24 h were: 3-indoleacetic acid 1.7 (normal); 2.5–9.4 (PKU); indican 6.24 (normal); 14.9–24.6 (PKU).

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

Maximal rate of renal tubular reabsorption of glucose (TmG) was determined in a 9-month-old girl with congenital intestinal malabsorption of glucose and galactose associated with constant glucosuria. At the time of the procedure, the patient had attained normal growth and development and was enjoying good health following a 5-month dietary regimen which excluded virtually all carbohydrates other than fructose. The standard glucose titration of renal tubules was carried out, using 4 arterial plasma glucose concentrations (PG), each maintained over 3 consecutive 20-minute periods while the glomerular filtration rate was kept relatively constant. The following observations were made: 1. The rate of filtered glucose (FG) was found to exceed that of reabsorption (TG) at all PGlevels ranging from 31 to 243 mg%, revealing a very low renal plasma threshold. 2. A TmGof 76.7 mg/ min/1.73 m2was achieved at a PGlevel of 174 mg%, when FG/TG= 1.35. This amounts to 25% of the normal adult value, taken as 303 mg/min/1.73 m2. Compared with data on premature and full-term newborns, it reflects a profound deficiency of tubular reabsorption of glucose in our patient. 3. A marked drop of TGwas recorded during the final hour of titration with prolonged elevation of FG; and the observation was felt to be valid. A search of the literature revealed that others have observed the same phenomenon in subjects with suboptimal tubular reabsorption of glucose relative to the filtered load.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID