摘要:

ExtractIn the present study, alcohol dehydrogenase activity (ADH) has been measured in human liver tissue during development, and a comparison made between certain kinetic properties of crude enzyme preparations from fetal and adult liver.The fetal livers were obtained from legal abortions. The liver tissue from children and adults was acquired during surgery of the abdomen in cases where no macroscopic abnormality of the livers was observable. The liver tissue was frozen immediately after excision. Studies indicated that the enzyme activity was stable at −20° for up to 6 days. All the determinations were made within 24 hours of the liver being sampled.A 10% liver homogenate was prepared in ice-cold 0.25 M sucrose containing 1 % Triton X-100. After centrifugation of the homogenate for 10 minutes at 5000 ×g at 3°G, samples were taken from the supernatant for protein determination and for enzyme assays. Table I presents the enzyme activity levels in human liver during the development from a fetus to an adult organism. The results are expressed as milliunits per g liver wet weight and per 100 mg soluble liver protein. ADH activity is detectable in 2-month-old fetuses, although it amounts to no more than 3–4: % of adult activity. Activities of adult range are found after 5 years of age. Considerable varation exists in the activity of adult livers.The relationship between pH and the rate of reaction appears in figure 1. The final pH figures of the reaction mixtures are given; these were determined with a Radiometer pH meter. Adult human liver ADH has a pH optimum of about 10.4, and the pH optimum for the fetal enzyme preparations is 10.0.Lineweaver-Burk analyses which illustrate the relationship between the concentration of ethanol and NAD, and the ADH activity in adult and fetal liver are presented in figures 2 and 3. The results presented are typical of three cases studied in each group. Close agreement was found for all constants in the different enzyme preparations examined. The apparent Kmvalues for ethanol were 3400 μM. and 1100 μM, and for NAD 70 μM and 150 μM in fetal and adult enzyme preparations respectively.SpeculationThese results do not constitute a foundation for a conclusion whether the fetal and the adult enzyme preparations are composed of a similar isoenzyme pattern. Studies which make use of purified enzyme and isoenzyme preparations are needed. Nevertheless, the results presented here suggest that variants may be found in alcohol dehydrogenase during development.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

ExtractHematocrit values were determined for nearly 7000 preschool children from low socio-economic backgrounds in five cities of the United States: Gainesville, Chicago, Houston, Jacksonville and Augusta. The mean hematocrit for the entire group was 36.32 %± 2.8%. Although severe anemia was unusual, the incidence of significant anemia (hematocrit <31 %) showed considerable variation from city to city, ranging from 0.6 to 7.7% and was unaffected by iron supplementation.SpeculationGeneralizations concerning the national incidence of nutritional anemia in preschool children on the basis of isolated local studies may not be warranted. Mass programs of dietary supplementation with hematinics are not indicated nationally; however, regional studies may reveal local needs.If simple, definitive and reliable laboratory techniques can be devised for use in suitably organized population groups, critical information on national health status may be obtained.Detection of a relatively large number of children with markedly elevated hematocrits is intriguing and should be investigated for relation to adult polycythemia.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

ExtractSerum from patients with cystic fibrosis of the pancreas (GFP) was found to disorganize the ciliary rhythm in explants of respiratory epithelium. This serum factor was present in all 75 patients with CFP and absent from the serum of 75 other patients having a variety of diseases with clinical features similar to those seen in GFP.The bio-assay method to detect the disorganized ciliary beat was performed in the following manner. Specimens of rabbit tracheal mucosa were placed and maintained in tissue culture flasks using standard tissue culture technique. After 4–6 days of incubation, specimens with beating cilia were removed from the flasks, placed on glass slides, exposed to a drop of test serum, covered with a sealed coverslip, and observed at room temperature with a magnification of 550 using phase contract illumination. A disorganized beat was usually observed within 5–10 minutes and persisted for a period of up to one hour.The serum factor was found to be heat labile, nondialysable, and precipitated with the euglobulins. Ghromatographic examination of serum from a patient with CFP on a column of Sephadex G-200 showed that the serum factor was eluted with the macroglobulin fraction as well as between the gamma globulin and albumin peaks.The serum factor was also detected in the parents of children with cystic fibrosis; however, the concentration of the factor appeared lower. The native sera from parents produced a disorganized beat in 7 of 25 cases. Upon concentrating the euglobulin fraction 2.5:1, the factor was detected in the remaining 18 sera. Similar concentration of sera from control patients resulted in only one positive reaction in the 25 sera tested. In addition, a ten-fold concentration of euglobulin from normal controls failed to disorganize the ciliary beat.SpeculationAlthough the mode of action of the serum factor has not been determined, the macromolecules in the serum may alter transport of electrolytes, thereby producing changes in the action potential within the cell and resulting in a disorganized ciliary beat. This postulate may have also some relation to the pathogenesis of the disease in view of the recent observation by Mangos and McSherry [7] that saliva of patients with GFP inhibits sodium transport.

ISSN:0031-3998    

出版商:OVID    

年代:1967

数据来源: OVID

摘要:

ExtractClearance of I125-labelled Type II pneumococci in immune and nonimmune rabbits was determined at 15, 30, 45 and 60 minutes after an injection of 1 × 109organisms (fig. 1). The patterns of uptake by the spleen and liver in immune and nonimmune rabbits differed in several major respects. The overall uptake by the liver exceeded that of the spleen in control and immune animals by a factor of at least 10 at each interval examined, this being most striking in the immune group. The spleen had a consistently higher capacity for uptake per unit of weight than the liver at all time intervals examined. This effect was found in immune as well as in nonimmune animals. The type specificity of this organ uptake pattern of response was determined by challenging an immunized group with a type of organism which differed from the immunogen. The pattern of uptake resembles that of non-immunized rabbits. Studies using passive immunization with type specific and heterologous type antisera confirmed these findings.SpeculationThe results obtained indicate more efficient function of the spleen in nonimmune clearance of these microorganisms but greater activity per unit of weight than the liver in both groups. The liver, although dependent upon type specific antibody for maximal clearance, was found to bear the total greatest burden of both immune and nonimmune clearance. Thus the capacity of the spleen for clearance of single episode of bacteremia may have considerable significance in the absence of specific antibody, in initiating a rapid local specific immune response there.

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

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