Extracellular pH (pH(e)) is lower in many tumors than in the corresponding normal tissue. The significance of acidic pH(e) in the development of metastatic disease was investigated in the present work. Human melanoma cells (A-07, D-12, and T-22) were cultured in vitro at pH(e) 6.8 or 7.4 (control) before being inoculated into the tail vein of BALB/c nu/nu mice for formation of experimental pulm...

Enterobacteria have developed numerous constitutive and inducible strategies to sense and adapt to an external acidity. These molecular responses require dozens of specific acid shock proteins (ASPs), as shown by genomic and proteomic analysis. Most of the ASPs remain poorly characterized, and their role in the acid response and survival is unknown. We recently identified an Escherichia coli ge...

Physicochemical analyses were carried out to evaluate 27 samples of honeys from three species of the Brazilian genus Melipona (M. capixaba, M. rufiventris and M. mondury) from Espírito Santo and Minas Gerais States. The parameters water activity (Aw), percentage of soluble solids (Brix %), pH, acidity (meq/Kg) and moisture (%) were evaluated. The honey characteristics obtained from these sample...

A solid-phase reagent for determination of urinary specific gravity (relative density) is described. This reagent strip, similar to others in the "N-Multistix" series (Ames), contains a polyacid whose acidity is sensitive to the ionic concentration in the urine in which it is immersed. As the acidity of the polyacid changes, pH changes are detected by a pH indicator within the reagent strip. In...

The minerals from which a soil is formed partly determine whether it is acid or alkaline. Soils formed from acidic rocks have a lower pH than those formed from basic rocks or alkaline parent material. Rainfall affects soil acidity development by leaching basic elements such as calcium, magnesium, potassium, and sodium from the soil profile, leaving the acidic elements: hydrogen, aluminum and ma...

Malfunction of the lower esophageal sphincter results in acid reflux into the esophagus. Reflux is mostly episodic so that the esophagus is not often presented with a continuous acid load. Prediction of esophageal disease related to reflux takes into account the pH of the refluxate and the duration of reflux. Expulsion of the refluxate back into the stomach shortens the time of exposure. The vo...

Ulcer formation after pylorus ligation was assessed in control, testosterone treated and castrated male rats after cimetidine treatment. The stomach was studied for incidence of ulcers and its contents analysed for pH, volume, total acidity, free acidity, pepsin and mucin activity. Testosterone and cimetidine when used alone protected from ulceration while when used in combination the degree of...

The ingestion of corrosive agents frequently produces adverse effect on the esophagus and the stomach or on both. Agents of alkaline pH usually result in esophageal injury, and agents of acid pH often cause gastric damage. Squamous epithelium lining the esophagus is sensitive to alkaline agents; however, alkaline agents upon reaching the stomach are rapidly neutralized by the gastric acidity of...

Replicative aging in yeast is asymmetric-mother cells age but their daughter cells are rejuvenated. Here we identify an asymmetry in pH between mother and daughter cells that underlies aging and rejuvenation. Cytosolic pH increases in aging mother cells, but is more acidic in daughter cells. This is due to the asymmetric distribution of the major regulator of cytosolic pH, the plasma membrane p...

BACKGROUND The acidic pH of the stratum corneum (SC) is important for epidermal permeability barrier homeostasis. Acidification of the skin surface has been suggested as a therapeutic strategy for skin disorders such as atopic dermatitis (AD). OBJECTIVE We performed an animal study to evaluate the usefulness of acidification of SC for inhibition of AD lesions and to find out if the therapeuti...