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Anesthesiology Sep 1987The shapes of the distributions of gastric pH and hydrogen ion concentration [H+] were determined for each of 68 groups of patients scheduled for elective surgery under... (Comparative Study)
Comparative Study
The shapes of the distributions of gastric pH and hydrogen ion concentration [H+] were determined for each of 68 groups of patients scheduled for elective surgery under general anesthesia. The 68 groups comprised a total of 1,326 patients who had served as subjects in 13 of the authors' previously published studies. In general, the results showed that neither pH nor H+ was normally distributed; most of the pH distributions (47 of 68 = 69%) and most of the H+ distributions (53 of 68 = 78%) showed significant departure from the normal distribution. Moreover, the shapes of the distributions varied, depending upon the conditions under which gastric acidity was assessed. Groups receiving no medication for gastric acidity had positively skewed pH distributions (nonsymmetrical distribution with tail pointing to right and majority of cases in lower range), and groups receiving medications for the reduction of acidity had negatively skewed pH distributions (nonsymmetrical with tail pointing to left and majority of cases in upper range). The medications produced an inverse relationship between mean pH and skewness such that the skewness of the groups decreased from positive to negative as mean pH increased. For H+, all groups had positively skewed distributions, but the distributions were more positively skewed for groups receiving medications for gastric acidity. Again, the medication conditions produced an inverse relationship between mean acidity and skewness such that the groups became more positively skewed as the mean H+ decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Gastric Acidity Determination; Humans; Hydrogen-Ion Concentration; Statistics as Topic
PubMed: 3631613
DOI: 10.1097/00000542-198709000-00017 -
Tobacco Control 1997To determine whether manipulation of the pH of moist-snuff products by manufacturers could control the delivery of nicotine. (Review)
Review
OBJECTIVE
To determine whether manipulation of the pH of moist-snuff products by manufacturers could control the delivery of nicotine.
DATA SOURCES
Medline database 1966-97 using the following subject headings and keywords: nicotine, absorption, mouth mucosa, skin, hydrogen-ion concentration, smokeless tobacco, biological transport, and membranes; computer database of the tobacco bibliography maintained by the US Centers for Disease Control and Prevention's Office on Smoking and Health; bibliographies of pertinent journal articles, books, and governmental reports; personal communications with experts in nicotine pharmacology and addiction; and Brown & Williamson Tobacco Corporation documents in the Tobacco Control Archives of the University of California, San Francisco.
STUDY SELECTION
Included all relevant animal studies, in-vitro studies, nicotine replacement therapy trials, and human observational studies.
DATA SYNTHESIS
We found that the effects of pH on drug absorption have been well established in animal models for nicotine and many other acidic or basic compounds. Increased alkalinity promotes the absorption of nicotine and increases its physiological effects. Human studies, which are more limited, confirm these processes. For example, nicotine absorption is directly related to the pH when nicotine is delivered in either tobacco smoke or nicotine polacrilex gum.
CONCLUSIONS
Although other factors could influence the rate of nicotine absorption from oral tobacco, manipulating tobacco pH appears to be the primary means by which the speed of nicotine absorption is determined in moist-snuff products.
Topics: Administration, Oral; Animals; Humans; Hydrogen-Ion Concentration; Nicotine; Plants, Toxic; Saliva; Tobacco, Smokeless
PubMed: 9396107
DOI: 10.1136/tc.6.3.219 -
Anesthesiology Nov 1947
Topics: Anesthesia, Spinal; Hydrogen-Ion Concentration
PubMed: 20270617
DOI: 10.1097/00000542-194711000-00005 -
British Journal of Anaesthesia Sep 1963
Review
Topics: Cardiovascular Agents; Electrolytes; Hydrogen-Ion Concentration; Muscle Relaxants, Central; Pharmacology; Water-Electrolyte Balance
PubMed: 14066105
DOI: 10.1093/bja/35.9.546 -
Biophysical Journal Dec 2021
Topics: Hydrogen-Ion Concentration
PubMed: 34798062
DOI: 10.1016/j.bpj.2021.11.012 -
British Journal of Cancer Sep 1991
Review
Topics: Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Neoplasms
PubMed: 1911181
DOI: 10.1038/bjc.1991.326 -
Journal of Bacteriology Nov 1952
Topics: Cytoplasm; Enterobacter aerogenes; Escherichia coli; Gram-Negative Bacteria; Hydrogen-Ion Concentration
PubMed: 12999709
DOI: 10.1128/jb.64.5.769-770.1952 -
Current Biology : CB Oct 2022The mechanisms by which plants sense the pH of their environment remained largely obscure. A recent study revealed that plants employ an interlaced bimodal...
The mechanisms by which plants sense the pH of their environment remained largely obscure. A recent study revealed that plants employ an interlaced bimodal peptide-receptor system to monitor the pH of the root apoplast, a readout that prioritizes either growth or defense.
Topics: Plants; Hydrogen-Ion Concentration; Peptides
PubMed: 36283355
DOI: 10.1016/j.cub.2022.08.079 -
Bacteriological Reviews Sep 1964
Review
Topics: Bacteria; Carotenoids; Cell Membrane; Electrons; Hydrogen-Ion Concentration; Ions; Lipoproteins; Metabolism; Microscopy; Microscopy, Electron; Pharmacology; Research
PubMed: 14220657
DOI: 10.1128/br.28.3.296-329.1964 -
Minerva Anestesiologica May 2010
Topics: Acid-Base Equilibrium; Acid-Base Imbalance; Humans; Hydrogen-Ion Concentration; Kidney; Specimen Handling; Urinalysis
PubMed: 20395889
DOI: No ID Found