The ionic quantity across the channel of the cell membrane decides the cell in a certain life state. The theory analysis that existed on the bio-effects of the electro-magnetic field (EMF) does not unveil the relationship between the EMF exerted on the cell and the ionic quantity across the cell membrane. Based on the cell construction, the existed theory analysis and the experimental results, an ionic probability wave theory is proposed in this paper to explain the biological window-effects of the electromagnetic wave. The theory regards the membrane channel as the periodic potential barrier and gives the physical view of the ion movement across cell-membrane. The theory revises the relationship between ion's energy in cell channel and the frequency exerted EMF. After the application of the concept of the wave function, the ionic probability across the cell membrane is given by the method of the quantum mechanics. The numerical results analyze the physical factors that influences the ion's movement across the cell membrane. These results show that the theory can explain the phenomenon of the biological window-effects.
Animals ; Biological Transport, Active ; Cell Membrane ; physiology ; radiation effects ; Cell Membrane Permeability ; physiology ; radiation effects ; Computer Simulation ; Electromagnetic Fields ; Ion Channels ; metabolism ; Ions ; metabolism ; Models, Biological

Normally the cornea has a water content varying between 76-78%, a state of relative dehydration maintained through its own metabolism by the active transport of water and ions across its limiting membrane, the epithelium and endothelium. If the metabolism is grossly disturbed or if the effectivity of the limiting membrane is impaired, the living cornea will swell by the absorption of the fluid. Corneal edema are developed due to trauma, inflammation, glaucoma, degeneration, and neuropathic and metabolic conditions. Essential corneal edema are encountered for which no cause can be found, the condition apparantly occuring without other ocular pathology. A 29 years old Korean lady has been found to have bilateral essential edema of the cornea.
Absorption ; Adult ; Biological Transport, Active ; Cornea ; Corneal Edema* ; Dehydration ; Edema ; Endothelium ; Epithelium ; Glaucoma ; Humans ; Inflammation ; Ions ; Membranes ; Metabolism ; Pathology ; Water

The metabolic transformation of the drugs containing carboxylic acid groups can lead to the formation of acyl glucuronide metabolites through catalysis by glucuronosyltransferase, and produce pro-acyl glucuronide intermediate metabolites with electronic activity. Then, protein or DNA adducts appeared after a series of non-enzyme or enzyme reactions. These adducts would change the protein activity and potentially lead to idiosyncratic and genotoxicity. In this paper, we discussed the chemical activity, drug-induced mechanisms, distribution and toxicity resulting from this metabolic activation for these drugs, and stated the status and prospects of research in this field.
Biological Transport, Active ; Biotransformation ; Carboxylic Acids ; metabolism ; toxicity ; DNA Damage ; drug effects ; Drug-Related Side Effects and Adverse Reactions ; Glucuronides ; metabolism ; toxicity ; Glucuronosyltransferase ; metabolism ; Hepatocytes ; metabolism ; Humans ; Pharmaceutical Preparations ; metabolism

OBJECTIVETo study the biotransformation by human intestinal flora, and the absorption and transportation characteristic in a model of human colon adenocarcinoma cell lines (Caco-2 cell) monolayer of d-corydaline (CDL) and tetrahydropalmatine (THP).

METHODCDL or THP was incubated with crude enzymes of human intestinal flora under the anaerobic environment and 37 degrees C conditions to transform CDL or THP. Caco-2 cell monolayer was used as an intestinal epithelial cell model for determination of the permeability of CDL or THP from apical side (AP side) to basolateral side (BL side) or from BL side to AP side. Transportation parameters and permeability coefficients (P(app)) were then calculated, and P(app) values were compared with the reported values for model compounds, propranolol as a well absorbed drug and atenolol as a poor absorbed drug. The concentration of CDL or THP was measured by HPLC coupled with photodiode array detector.

RESULTCDL or THP in the human intestinal flora incubation system did not happen biotransformation. In the Caco-2 cell monolayer model, the P(app) magnitudes of both CDL and THP were 1 x 10(-5) cm x s(-1) in the bi-directional transport, which were identical with propranolol. And their transports were concentration dependent between 0-180 min.

CONCLUSIONBoth CDL and THP may be stable in the human intestinal flora incubation system, and their absorption and transportation in the human Caco-2 cell monolayer model are mainly via passive diffusion mechanism.

Bacteria ; metabolism ; Berberine Alkaloids ; metabolism ; pharmacokinetics ; Biological Transport ; Biotransformation ; Caco-2 Cells ; Corydalis ; chemistry ; Drugs, Chinese Herbal ; metabolism ; pharmacokinetics ; Humans ; Intestinal Absorption ; Intestines ; metabolism ; microbiology ; Models, Biological

PURPOSE: alpha-Ketoglutarate (alphaKG), a Krebs cycle intermediate, is extensively used in the kidney as a fuel substrate and as a counter anion for organic acid secretion. It is known to be taken up by the proximal tubule cells via the brush-border as well as basolateral membranes. We explored biochemical characteristics of the brush-border and basolateral alphaKG transport systems in pars convoluta and pars recta of the proximal tubule, respectively. METHODS: Brush-border and basolateral membrane vesicles (BBMV and BLMV) were isolated from rabbit renal outer cortex and outer medulla by Percoll gradient centrifugation. Vesicular uptake of alphaKG was determined by rapid Millipore filtration method using alpha-14[C]KG as a substrate. RESULTS: Both BBMV and BLMV showed a Na-gradient dependent uphill transport of alphaKG. The systems in both membranes were similarly inhibited by Li and activated by Na (Hill coefficient of 1.4). Kinetic analyses indicated that the Na-alphaKG cotransporters in the BBMV had a lower substrate affinity as compared with those in the BLMV. The transport systems in BLMVs showed a similar Km but different Vmax between the outer cortex (Km: 34 uM, Vmax: 3.3 nmol/mg protein/10s) and outer medulla (Km: 37, Vmax: 1.8). On the other hand, the systems in BBMVs were different in both Km and Vmax between the outer cortex (Km: 194, Vmax: 3.3) and outer medulla (Km: 89, Vmax: 1.7). CONCLUSION: The findings suggest that both axial and apical to basolateral heterogeneity of the Na-alphaKG cotransport system in proximal tubules may be due to a physiological adaptation to efficiently utilize alphaKG in the kidney.
Adaptation, Physiological ; Biological Transport, Active ; Centrifugation ; Citric Acid Cycle ; Filtration ; Hand ; Ketoglutaric Acids ; Kidney Tubules ; Kidney* ; Membranes ; Population Characteristics ; Symporters

Animals ; Biological Transport, Active/physiology* ; Centrioles/metabolism* ; Cilia/metabolism* ; Mice ; Mice, Mutant Strains ; N-Acetylglucosaminyltransferases/metabolism*

Basal metabolic rate (BMR) is of great significance to the setting of daily energy requirements and the scientific diet guidance for the population. There are 3 kinds of measurement methods for BMR, including the direct calorimetry, the indirect calorimetry, and the equation estimation. The direct calorimetry method is difficult to implement and is only used in some special populations. The indirect calorimetry and the equation estimation are two methods that are currently used commonly. The indirect calorimetry is highly accurate and suitable for individual for basal metabolic measurement or datum collection via equation estimation. The equation estimation is simple and convenient, which is suitable for large samples.
Basal Metabolism ; physiology ; Biomedical Research ; Calorimetry, Indirect ; Energy Metabolism ; Humans

As a clean energy source and industrial material, hydrogen is very valuable. Electrolysis of water and chemical methods are well-known for producing hydrogen, however, all of these methods need additional energy supply. Besides highly energy cost, the chemical methods will lead to serious environment pollution. Compared with traditional methods, biological production of hydrogen has showed significant advantages. Bio-hydrogen can be produced by anaerobic and photosynthetic microorganisms during treatment of organic waste. It provides a low cost method for producing hydrogen gas, and a way of utilizing waste at the same time. This paper summarized the procedures of treatment of solid waste and the production of bio-hydrogen.
Bioelectric Energy Sources ; Biotransformation ; Hydrogen ; metabolism ; Refuse Disposal ; methods

Animals ; Biological Transport ; Blood-Brain Barrier ; metabolism ; Cell Membrane Permeability ; Chromatography, Liquid ; methods ; Humans ; Membranes, Artificial ; Permeability ; Pharmaceutical Preparations ; metabolism ; Pharmacokinetics ; Quantitative Structure-Activity Relationship ; Skin Absorption

Plant serine carboxypeptidase-like acyltransferases (SCPL-AT) have similar structural characteristics and high homology compared to the serine carboxypeptidase. They can transfer the acyl from acyl glucose esters to many natural products, participate in the acylation modification of plant secondary metabolites, enrich the structural diversity of natural products, and improve the physicochemical properties such as water solubility and stability of compounds. This review summarizes the structural characteristics, catalytic mechanism, functional characterization, and biocatalytic applications of SCPL-AT from plants. This will help to promote the functional characterization of these acyltransferase genes and the biosynthesis of useful plant secondary metabolites by synthetic biotechnology.
Acylation ; Acyltransferases/metabolism* ; Carboxypeptidases/metabolism* ; Plants/enzymology*