total abstention from food and water from sunrise to sunset during the month of  ramadan, is practiced by hundreds of millions of muslims throughout the world. this pattern of fasting during ramadan is different from the usual fasting as people are allowed to eat and drink between sunset and dawn but not after dawn. the amount and type of food (rich in protein, fat and sugar) eaten during the n...

Dehydration (body water deficit) is a physiologic state that can have profound implications for human health and performance. Unfortunately, dehydration can be difficult to assess, and there is no single, universal gold standard for decisionmaking. In this article, we review the physiologic basis for understanding quantitative dehydration assessment. We highlight how phenomenologic interpretati...

Dehydration (body water deficit) is a physiologic state that can have profound implications for human health and performance. Unfortunately, dehydration can be difficult to assess, and there is no single, universal gold standard for decision making. In this article, we review the physiologic basis for understanding quantitative dehydration assessment. We highlight how phenomenologic interpretat...

Natural selection is believed to be an unforgiving and relentless force in the evolution of life on earth. An organism that cannot adapt to a changing environment or an environment hostile to cell functions is at risk as a species. So it is important to understand the mechanisms used by plants, animals, and microorganisms in adapting to environments in the biosphere that would ordinarily denatu...

It is critical for cells to maintain a homeostatic balance of water and electrolytes because disturbances can disrupt cellular function, which can lead to profound effects on the physiology of an organism. Dehydration can be classified as either intra- or extracellular, and different mechanisms have developed to restore homeostasis in response to each. Whereas the renin-angiotensin system (RAS)...

Leaf shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly extreme during drought. However, little has been known of its correlation with physiology. Computer simulations of the leaf hydraulic system showed that a reduction of hydraulic conductance of the mesophyll pathways outside the xylem would cause a strong decline of leaf hydraulic conduct...

Seed dehydration is the normal terminal event in the development of orthodox seeds and is physiologically related to the cessation of grain dry mass accumulation and crop grain yield. For a better understanding of grain dehydration, we evaluated the hypothesis that hydraulic conductance of the ear decreases during the latter stages of development and that this decrease results from disruption o...

Aquaporins (AQPs) are water channel proteins facilitating movement of water across the cell membrane. Recent insect studies clearly demonstrate that AQPs are indispensable for cellular water management under normal conditions as well as under stress conditions including dehydration and cold. In the present study we cloned an AQP cDNA from the Antarctic midge Belgica antarctica (Diptera, Chirono...

The supraoptic nucleus (SON) of the hypothalamus is an important integrative brain structure that coordinates responses to perturbations in water balance and regulates maternal physiology through the release of the neuropeptide hormones vasopressin and oxytocin into the circulation. Both dehydration and lactation evoke a dramatic morphological remodeling of the SON, a process known as function-...