Saliva flow measurements and SDS-PAGE separation of human whole saliva freshly collected after oral stimulation with citric acid (sour), aspartame (sweet), iso-α-acids (bitter), mono sodium l-glutamate (umami), NaCl (salty), 6-gingerol (pungent), hydroxy-α-sanshool (tingling), and hydroxy-β-sanshool (numbing), followed by tryptic digestion, nano-HPLC-MS/MS, and label-free protein quantitation demonstrated a stimulus- and time-dependent influence of the dietary chemosensates on salivation and the salivary proteome composition. Gene ontology enrichment analysis showed evidence for stimulus-induced alterations of the saliva proteome to boot an efficient molecular defense network of the oral cavity, e.g., 6-gingerol increased salivary lactoperoxidase activity, catalyzing the oxidation of thiocyanate to produce the antimicrobial and antifungal hypothiocyanate, from 0.37 ± 0.02 to 0.91 ± 0.05 mU/mL 45 s after stimulation. In comparison, oral citric acid stimulation induced an increase of myeloperoxidase activity, catalyzing the chloride oxidation to generate antimicrobial hypochloride in saliva, from 0.24 ± 0.04 to 0.70 ± 0.1 mU/mL as well as an increase of salivary levels of lysozyme, exhibiting antimicrobial activity on Gram-positive bacteria, from 6.0-10 to 100-150 μg/mL. Finally, microbial growth experiments clearly demonstrated for the first time that the increase of the salivary lysozyme abundance upon oral citric acid stimulation translates into an enhanced biological function, that is an almost complete growth inhibition of the two lysozyme-sensitive Gram-positive bacteria tested.

After a single oral 600 mg dose, ofloxacin concentrations were measured in lung tissue, whole blood and plasma in 11 patients undergoing thoracotomy for a bronchial malignancy. To correct for blood contamination in the tissue samples, the tissue haemoglobin content was measured using a method based on the binding of haemoglobin by haptoglobin. Ofloxacin concentrations in plasma and whole blood did not differ significantly. The calculated blood content in the tissue samples was 0.12 +/- 0.05 ml/g lung tissue. After correction for blood admixture, the mean lung tissue concentration 2 h after administration of ofloxacin was 17.7 +/- 9.2 micrograms/g. At the same time the mean plasma concentration was 8.7 +/- 4.2 mg/l (P less than 0.02). The high concentration of ofloxacin obtained in lung tissue does not result from the preparation technique. After a single 600 mg dose the tissue concentrations proved to exceed MIC values for most pathogens frequently involved in respiratory tract infections.

A continuous procedure for the determination of leucine aminopeptidase is described. L-leucinamide is used äs Substrate and the liberated ammonia is determined with the glutamate dehydrogenase reaction. The enzyme is Mn 2 +-activated and 30 / MnCl 2 is necessary for an optimal activity measurement. Influence of buffer type, buffer concentration and pH are reported together with the apparent K m values of leucine aminopeptidase for L-leucinamide and of glutamate dehydrogenase for 2-oxoglutarate. Amastatin, a potent inhibitor, iiihibits the reaction of leucine aminopeptidase completely, whereas it has no inhibitory effect on the reaction with glutamate dehydrogenase. The normal reference interval for leucine aminopeptidase is 12 -65 U/l at 37 °C. The properties of the enzyme are discussed. Eine kontinuierliche Methode zur Bestimmung von Leucinaminopeptidase in menschlichem SerumZusammenfassung: Es wurde ein kontinuierliches Verfahren zur Bestimmung von Leucinaminopeptidase mit L-Leucinamid als Substrat untersucht. Das freigesetzte Ammoniak wird mit der Glutamatdehydrogenase-Reaktion bestimmt. Das Enzym wird aktiviert von Mn 2 + und 30 / von MnCl 2 ist für eine optimale Aktivität erforderlich. Der Einfluß von Art des Puffer, Pufferkonzentration und pH wird zusammen mit dem scheinbaren # m -Wert von Leucinaminopeptidase für L-Leucinamid und von Glutamatdehydrogenase für 2-Oxoglutarat beschrieben. Amastatin hemmt Leucinaminopeptidase vollständig, während es keine hemmende Wirkung auf die Glütamatdehydrogenase-Reaktion hat. Der Referenzbereich beträgt 12-65 U/l bei 37 °C. Die Eigenschaften des Enzyms werden diskutiert.

4‐methylcatechol, phenolic acids from the benzoic and cinnamic series, flavan 3‐ols and L‐tyrosine were tested to determine the catalytic behavior of barley peroxidases (POD) at the expense of hydrogen peroxide. A chronometric assay using L‐ascorbic acid was described for determining the peroxidatic activity of basic and neutral/anionic enzymatic fractions. The effects of hydrogen donors H2O2, and Ca++ ion concentrations and pH were studied to set maximal conditions for POD measurement. The sensitivity to endogenous phenolic compounds (ferulic and p‐coumaric acids, (+) catechin) along with caffeic acid for POD fractions was investigated and compared with their response versus guaiacol. Under the conditions tested, syringic and sinapinic acids as well as L‐tyrosine were very weakly oxidized by POD from barley, whereas ferulic and caffeic acids were rapidly transformed. Levels of POD activity extracted from barley, green malt and kilned malt crude extracts were thereafter compared.