ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryThe isozymic composition of phosphofructokinase (EC. 2.7.1.11) from human fetal tissues has been investigated by immunological characterization, electrophoresis, purification, and SDS-polyacrylamide gel electrophoresis of the dissociated subunits.One of the characteristics of fetal tissues is the indiscriminate expression by all the cells of two or three of the basic forms of phosphofructokinase without any isozyme really corresponding to a specifically fetal form. In particular, L-type enzyme, identical to the highly regulatory enzyme synthesized by the adult hepatocytes, is found in most fetal tissues, especially in muscle and brain. M-type subunits are also detected in most of the organs and constitute the major form in fetal muscle and adrenals. F-type subunits are predominant in fetal stomach and yolk sack and are practically the only form in fetal heart.Some electrophoretic and chromatographic differences between fetal and adult M-type phosphofructokinase exist; whether their nature is genetic or posttraductional is so far unknown.Some differences (of molecular weight and chromatographic properties) are also detected between the fetal L-type subunits and enzyme from adult granulocytes. A mild proteolytic attack of the former by subtilisin transforms it into an enzyme form indistinguishable from granulocyte phosphofructokinase.SpeculationIn the fetus as well as in adult tissue, phosphofructokinase could be coded by a three-gene-system, coding for the M, L, and F subunits. The M and L subunits could undergo some postsynthetic changes, increasing the heterogeneity of phosphofructokinase in the various tissues.One of the characteristics of the “fetal state” could be the indiscriminate expression of several of the basic genes; differenciation would be associated with the selective repression of the “unuseful” forms. It is expected that in cancer a reappearance of the normally repressed forms would occur.Phosphofructokinase differs, therefore, from other enzymes which p ssess forms expressed in all tissues in the fetal period and have tissue-specific isozymes that appear later. These isozymes (like liver aldolase and muscle creatine kinase) are strong tissue markers, whereas phosphofructokinase isozymes appear to be weak tissue markers.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryAltered exocrine gland function is characteristic of cystic fibrosis (CF). This study was undertaken to determine the relationship between pancreatic and salivary exocrine dysfunction in CF. We have measured serum pancreatic (P) and salivary-like (S) isoenzyme concentrations in CF patients, their obligate heterozygote parents and normal controls (N) using a quantitative gel-electrophoretic method. Our results show that serum levels of these isoenzymes correlate with the respective pancreatic and salivary gland amylase output and, therefore, can be used as measures of pancreatic and salivary exocrine function. Thus, P isoenzyme levels are low in CF patients with pancreatic insufficiency (mean ± S.D.: 1.3 + 0.6 starch units per liter versus 5.8 ± 1.7 for the N group,P< 0.001). In contrast, P isoenzyme levels are elevated in CF patients with adequate pancreatic function (12.0 ± 5.3;P< 0.002 versus N). Whereas P isoenzyme levels differentiate CF patients with pancreatic insufficiency from those with adequate pancreatic function, S isoenzyme levels are equally elevated irrespective of pancreatic function (12.5 ± 5.3 and 12.5 ± 5.2versus8.1 ± 2.7 for the N group,P< 0.001 and < 0.01, respectively). Thus, increased salivary amylase levels in CF patients are not due to a compensatory mechanism for reduced pancreatic amylase output, but rather are intrinsic to CF. In those patients with adequate pancreatic function, the increased S isoenzyme levels correlate with increased P levels (r= 0.72), indicating defective control of both pancreatic and salivary exocrine secretion in CF. In obligate heterozygote samples, P isoenzyme levels are increased (7.6 ± 2.5;P< 0.05 versus N) whereas S isoenzyme levels are normal (8.2 ± 5.6), indicating that this defect is partially expressed in the carrier state. We conclude that elevated saliva amylase and altered serum amylase isoenzyme levels in the CF patient and carrier state are due to a generalized defect in exocrine gland secretory regulation in CF.SpeculationWe speculate that the altered exocrine secretion in cystic fibrosis patients and their parents is due to the presence of an extra, cystic-fibrosis-associated, stimulatory agent and that the exocrine pancreas is more sensitive to this agent than are the salivary glands.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryThe major variation in effect between undiluted cystic fibrosis and heterozygote sera on rabbit tracheal epithelium was in terms of the time after exposure at which changes occurred. Exposure to both types of sera for 3 min caused release of goblet cell mucus and ciliary resorption possibly by apical swelling of columnar cells. Fusion of cilia and loss of microtubule pairs increased markedly through 60 min exposure. After 60 min exposure to heterozygote sera, a thick mucus net formed over many regions of the ciliary surface trapping cilia. Cilia from these areas showed separation occurring between adjacent pairs of peripheral microtubules with individual microtubule pairs remaining intact. Prolonged exposure (60 min) to cystic fibrosis serum resulted in increased mucus secretion and massive columnar cell loss. Some columnar cells were extensively swollen and basal cells showed significant changes. Control serum had no effect on tracheal epithelium over the same time span. Such cystic fibrosis serum-induced changes are characteristic of what one would expect from cells undergoing extensive cytolysis and are much more severe than those induced by heterozygote sera.SpeculationA component in cystic fibrosis serum may alter membrane regulation resulting in increased levels of intracellular calcium in ciliated and goblet cells. This increase may account independently for ciliary alterations and mucus secretion which ultimately cause ciliary dyskinesia. Prolonged calcium influx may account for the cytolysis of epithelial cells. Comparable factors may be responsible for mucus stagnation and respiratory dysfunction in patients with cystic fibrosis.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryFull-term newborns (FTN) plasminogen was evaluated by different techniques (affinity chromatography, immunologic technique, casein method, and chromogenic substrate). The functional activity of the FTN plasminogen was about 50% of that of the adult. This suggests the possible existence of a functional anomaly of plasminogen in FTN.FTN plasminogen aminoacids were studied, and, besides small qualitative anomalies, a decrease in amino acid residues per mole of protein and a differentN-terminal amino acid were detected.SpeculationThe existence of a functional anomaly in full-term newborns plasminogen has been suggested. The possible role of this anomaly in the pathogenesis of the hemorraghic diseases of the neonate and in hyaline membrane disease is not known, thus, the identification of this anomaly could contribute to a better understanding of these diseases.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryAnesthetized young rabbits were ventilated for 6 hr at 20 cm H2O peak airway pressure using air nebulized with water at 22°C (cold nebulized group,n= 11), at 36°C (warm nebulized group,n= 11) and humidified air at 36°C (warm humidified group,n= 10). Their biochemical status during ventilation and pulmonary morphology at autopsy were compared to those of ten control rabbits. Both nebulized groups had particulate water in the inspired air and water of condensation in the endotracheal tube.The rabbits ventilated with warm humidified air and the control group breathing spontaneously maintained their blood pressure and pHa within physiologic range. Rabbits ventilated with air nebulized with water at 22 and 36°C had a significant decline in mean blood pressure (96 mm Hg → 61 mm Hg in cold nebulized and 91 mm Hg → 61 mm Hg in warm nebulized) and mean pHa (7.43 → 7.23 in cold nebulized and 7.42 → 7.31 in warm nebulized). All rabbits in the control and warm humidified groups survived the study whereas 9 of 22 in the nebulized groups died before completion of study (P< 0.005).Morphometric analysis revealed a significant increase in the mean vascular wall thickness in both nebulized groups of rabbits when compared to that in the control and warm humidified groups (P< 0.05). The cold nebulized group also had significantly less air space and correspondingly more interstitial thickness and intraalveolar edema (P< 0.05) compared to control and warm humidified groups. These findings of pulmonary parenchymal damage in rabbits ventilated with air containing particulate water and the greater degree of both physiologic and anatomic change evident in the cold nebulized animals suggest that particulate water and low inspired air temperature may contribute to the genesis of pulmonary damage during intermittent positive pressure ventilation.SpeculationThe phenomenon of reflex pulmonary hypertension following instillation of small quantities of fresh water to the lung (5) might occur even if miniscule amounts of particulate water are delivered during intermittent positive pressure ventilation. Particulate water in inspired air could therefore play a role in the pulmonary parenchymal damage seen in babies treated with intermittent positive pressure ventilation. Failure to maintain temperature of the inspired air at body temperature during intermittent positive pressure ventilation (25) may also have a deleterious effect in the human infant.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryPulmonary maturation in diabetic pregnancy has been studied in the 20-day-old fetuses of manifest diabetic rats. The animals were either untreated or treated with insulin. The diabetic state was induced by a single IV injection of streptozotocin given about 2 wk before the onset of pregnancy. The biosynthesis of lung surfactant was estimated by monitoring the rate of incorporation of [methyl-3H]choline into phosphatidylcholine and lysophosphatidylcholine in fetal lung slices.In the untreated group, the biosynthesis of both phosphatidylcholine and lysophosphatidylcholine were decreased in the fetal lung. Insulin treatment abolished the decrease in the phosphatidylcholine biosynthesis, whereas the lysophosphatidylcholine biosynthesis reamined depressed. Light and transmission electron microscopical studies indicated a delayed pulmonary maturation in the untreated offspring accompanied by a decreased cytoplasmic content of glycogen in the alveolar epithelial cells.SpeculationIt is suggested that, in diabetic pregnancy, respiratory distress syndrome becomes manifest after a diminished availability of surface-active dipalmitic phosphatidylcholine in the fetal lung, resulting from a specific inhibition of the lysophosphatidylcholine pathway.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryErythrocytes of patients with Duchenne muscular dystrophy have been found to have elevated levels of spermine, a polyamine with a membrane-stabilizing action. Although a specific, increased spermine concentration is an additional biochemical abnormality documenting the involvement of erythrocyte membrane in Duchenne muscular dystrophy.Normal level of spermine were found in female carriers.SpeculationThe generalized cell membrane involvement in Duchenne muscular dystrophy and in other myopathies may be inferred by an increased cellular concentration of substances, such as the polyamine spermine, which are involved in the maintenance of cellular stability.Unfortunately, this characteristic of cells from myopathic patients is not utilizable for diagnostic purpose because it is not specific for a single myopathy, and it is not shared by the cells of healthy carriers.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SummaryThe lysosomal storage material in cultured fibroblasts from patients with various lysosomal storage diseases was characterized by fluorescence microscopy using lectins specific for different saccharide moieties. In normal fibroblasts and cultured amniotic fluid cells lectins specific for mannosyl and glucosyl moieties, Con A and LcA gave a bright perinuclear cytoplasmic staining corresponding to the localization of endoplasmic reticulum in the cells. All other lectins stained the Golgi apparatus as a juxtanuclear reticular structure.In fucosidosis fibroblasts, only lectins specific for fucosyl groups LTA and UEA, distinctly stained the lysosomal inclusions. The lysosomes in mannosidosis fibroblasts did not react with Con A and LcA, both specific for mannosyl moieties of glycoconjugates, but were brightly labeled with WGA, a lectin specific for JV-acetyl glucosaminyl moieties. In I-cell fibroblasts, the numerous perinuclear phase-dense granules, representing abnormal lysosomes, were labeled with every lectin used. In fibroblasts from patients with Salla disease, a newly discovered lysosomal storage disorder, the lysosomes were brightly stained only with LPA, indicating the presence of increased amounts of sialic acid residues in the lysosomal inclusions.SpeculationStaining of cultured cells with sugar-specific lectins may reveal interesting aspects on the pathogenesis of lysosomal storage phenomenon. In some instances, the method can be of use as an auxiliary technique in prenatal diagnosis of lysosomal storage diseases.

ISSN:0031-3998    

出版商:OVID    

年代:1980

数据来源: OVID