摘要:

Information is conflicting as to whether nitric oxide plays a role in the pathogenic mechanisms of zinc deficiency. Our series of research using a rat model demonstrated that inducible nitric oxide synthase in the intestine is upregulated by zinc deficiency when challenged by the injection of IL-1α, and the systemic administration of nitric oxide synthase inhibitor attenuates both intestinal damage and inflammatory skin lesions induced by zinc deficiency. Evidence from both transcription and translation levels indicates that inducible nitric oxide synthase, one of three nitric oxide synthase isoforms, has already been induced in the skin and intestine of zinc-deficient animals, whereas it is not generally expressed in normal tissues. On the other hand, total nitric oxide synthase activity in the intestine of zinc-deficient animals is significantly lower than that in controls, indicating that zinc deficiency may induce a potential vulnerability to nitric oxide rather than an absolute increase of nitric oxide synthase activities. Tissue zinc and metallothionein levels are significantly decreased in zinc-deficient rats, suggesting lowered antioxidative capability. Whether nitric oxide is destructive in inflammation may depend on the status of homeostasis such as the zinc level of tissues and the balance between the three nitric oxide synthase components, although identifying an absolute increase of nitric oxide production is of importance. Defining the role of nitric oxide provides the rationale for new strategies in zinc deficiency.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Lipophilic molecules can passively diffuse across cell membranes, a process that is driven by the concentration gradient, by availability of acceptors to facilitate desorption from the bilayer, and by cellular metabolism. However, evidence has accumulated that supports the existence of specialized, protein-facilitated membrane transport systems for many lipophilic molecules. This has generated considerable debate regarding why such systems need to exist. The present review summarizes recent developments related to the membrane transport systems for cholesterol and fatty acids, which have been shown to involve structurally related proteins. General similarities of the cholesterol and fatty acid systems to other lipid transport systems (briefly discussed in the Introduction section) are highlighted in the Conclusion section. The overall aim of the present review is to illustrate why lipid transporters are neededin vivo, and how they accomplish specific functions that can not be met by lipid diffusion alone.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

This review focuses on the advances made in recent years in the understanding of the multivitamin transporter, a unique and important transporter that transports not one but three different unrelated water-soluble vitamins namely, pantothenate, biotin and lipoate. The transport process mediated by the transporter is active and is energized by the transmembrane sodium ion gradient as well as the membrane potential. The transporter belongs to the sodium-coupled glucose transporter family. The ubiquitous expression of this transporter in mammalian tissues and the fact that it is highly conserved across the species indicate the nutritional relevance and importance of this transporter.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Iron homeostasis is regulated with respect to uptake, storage and utilization. Newer work is presented that defines proteins responsible for iron transport, sequestration and sensing, and that addresses their regulation at the cellular and organismal levels by ambient iron concentrations, demand for erythropoiesis, body iron burden, and redox stimuli.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The leptin and lipogenic enzyme genes contain the common DNA sequences of binding sites for Sp1 proteins. These sites appear to be responsible for glucose/insulin stimulation and polyunsaturated fatty acid suppression. In rat adipose tissue leptin and lipogenic gene expression is similarly regulated by nutritional manipulation. Interestingly, leptin has the ability to down-regulate lipogenic enzyme expression.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Malnutrition predisposes to tuberculosis, and tuberculosis causes ‘consumption’. Starting from current advances and historic findings in epidemiology and immunology, we can hope to decipher the effects of macro- and micronutrient deficiency upon tuberculosis, the contribution of immune response to the pathogenesis of wasting, and the best approach to its treatment.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Recent studies have focused on the current dietary intake of cystic fibrosis patients, the impact of nutritional support on both the nutritional status and clinical outcome variables, and the effects on the nutritional status of antibiotic therapy and surgical treatment of meconium ileus. In addition to weight and height, skinfold measurements, bioelectrical impedance analysis and dual energy X-ray absorptiometry have been employed for the determination of nutritional status. A proton pump inhibitor has been used successfully along with pancreatic enzymes for the improvement of fat absorption. Attention has been paid to resting energy expenditure during pulmonary exacerbations, to vitamin K function in bone mineralization and to risk factors for low bone mineral density in cystic fibrosis. The relationships between glutathione and nutritional status have been studied, along with possible interactions with albumin, a potent antioxidant. Finally, a beneficial effect of docosahexaenoic acid on cystic fibrosis pathology has been suggested, but this requires further critical evaluation.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The amino acid requirements of the parenterally fed neonate are poorly defined. Newborn infants are at risk for amino acid deficiency and toxicity, due to lack of small intestinal metabolism and metabolic immaturity. We discuss recent evidence that identifies inadequacies of commercial amino acid solutions with respect to the balance and quantity of aromatic amino acids, and sulphur amino acids. We present data demonstrating that impaired small intestinal metabolism (or lack of first pass metabolism) alters the whole body requirement for methionine, threonine, and arginine, and discuss the potential adverse effects of excess or inadequate parenteral amino acid intake.

ISSN:1363-1950    

出版商:OVID    

年代:2000

数据来源: OVID