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Biomedical subjects

F Lutz

Publications and source records attributed to F Lutz.

At least 181 records · Page 10Linked to original sources
PubMed1989

Dentin abrasion (RDA), enamel abrasion (REA) and polishing scores of dentifrices sold in Switzerland.

Assessments of the abrasion of hard dental tissues produced by different dentifrices are usually carried out on extracted teeth in the laboratory. The tests most commonly used to measure dentifrice abrasion on dentin and enamel are the radiotracer (radio-active) and profilometry methods. The radiotracer dentin (RDA) and enamel (REA) abrasion scores of the 32 dentifrices were determined using the ADA specifications. RDA and REA scores are related to a standard abrasive, calcium pyrophosphate (Ca2P2O7), which is assigned a score of 100 for the RDA method and 10 for the REA method. The same abrasive was used as the standard in the enamel polish study and assigned a score of 100. The RDA scores of the dentifrices tested varied from 37 to 203, the REA scores from 1.0 to 11.7, and the polishing scores ranged from 19.63 to 96.88. Half the dentifrices tested had RDA scores below 100.

Dental Enamel↗
PubMed1989

[Microbiologic in vitro comparison of plaque-inhibiting mouthwashes].

The colonization on rat molars of S. sobrinus OMZ 176, S. mutans OMZ 376, or a combination S. sanguis OMZ 9 and S. sobrinus OMZ 176 after a short exposition to various fluoride solutions and disinfectants was tested in vitro. The test solutions included Act, Candida, Veadent, sodium fluoride, amine fluoride, stannous fluoride, zinc fluoride hexetidine, stannous fluoride/amine fluoride solutions, chlorhexidine and water. The sterilized rat molars were immersed in the above test solutions for 60 seconds, then incubated with streptococci in broth for 8 hours, again dipped into the same test solutions for 60 seconds and reincubated for an additional 30 hours. The streptococcal suspension contained 14C labelled sucrose solutions. The deposits on the molars were dissolved in 6N potassium hydroxide during 16 hours. Finally, the beta rays emitted by the dissolved radiolabelled suspension were counted using a scintillation counter. The sodium fluoride containing solutions exerted no or a very limited effect on the bacterial deposits. In contrast to the other test solutions, sanguinaria extract (Veadent mouth rinse) mildly inhibited the S. sobrinus and S. mutans deposits, but plaque formation by the combination of streptococci was not hampered. Zinc fluoride/hexetidine, amine fluoride and stannous fluoride/amine fluoride solutions had a distinct and significant inhibitory effect on S. sobrinus and S. mutans deposits, but only a weak effect when mixed cultures were used for plaque formation. Chlorhexidine significantly inhibited the deposits of the three bacterial strains used in these experiments.

Animals↗
PubMed1989

[Oral health--the status of knowledge 1985. An analysis of a repeated survey of 761 Swiss recruits].

Concurrent with an epidemiological study, 761 military recruits were questioned about their attitudes towards dentists, dental treatment and oral hygiene habits. In addition, their knowledge of periodontal diseases and their prevention was evaluated, as were their smoking and snacking habits. Such recruits had been similarly questioned 11 years previously. Both the present and the previous studies showed that the recruits had a very positive attitude towards their dentitions, expressing a defined desire for good oral health. Oral hygiene habits, particularly daily toothbrushing, improved during the decade and were graded as acceptable. However, the recruits generally had a poor impression of dentists and their individual treatments. The number of recruits presenting for the emergency treatment of pain increased by 20%. Of this group, recruits who only sought dental checkups sporadically increased four times compared to the previous study. Confirming results of the previous study, knowledge of periodontal diseases and its prevention were poor. This may indicate a lack of clearly explained information by the dental teams which previously and presently treated these recruits. The development of a consumer society was expressed by the increased snacking habits. In contrast to what was expected, the information about dental diseases and the motivation of recruits by dental personnel and in the schools to better dental health should be improved.

Attitude to Health↗
PubMed1988

Pathway of phospholipase C activation initiated with platelet-derived growth factor is different from that initiated with vasopressin and bombesin.

The mode of phospholipase C activation initiated with platelet-derived growth factor (PDGF) has been studied in comparison with that initiated with vasopressin and bombesin in a rat fibroblast line, WFB. Stimulation of WFB cells by PDGF, vasopressin, and bombesin elicites rapid hydrolysis of polyphosphoinositides and an increase in cytoplasmic free Ca2+ concentration ([Ca2+]i). On stimulation by PDGF, there was a lag period of about 10 s before an increase in [Ca2+]i. No measurable lag period was observed in the [Ca2+]i response induced by vasopressin or bombesin. Pretreatment of WFB cells with phorbol 12-myristate 13-acetate profoundly inhibited inositol phosphate formation evoked by vasopressin and bombesin, but enhanced to some extent inositol phosphate formation stimulated by PDGF. In membranes prepared from WFB cells, GTP markedly augmented inositol polyphosphate formation induced by vasopressin and bombesin. It was not successful in showing the PDGF-stimulated formation of inositol phosphates in the membrane preparation. The effects of GTP, guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) on polyphosphoinositide hydrolysis stimulated by growth factors were studied in WFB cells made permeable to nucleotides by treatment with either saponin or Pseudomonas aeruginosa cytotoxin. PDGF, vasopressin, and bombesin elicited inositol phosphate production in the permeabilized WFB cells in the absence of added GTP. GDP beta S, a competitive inhibitor of GTP-binding proteins (G-proteins), markedly reduced the bombesin- and vasopressin-stimulated production of inositol phosphates. However, the PDGF-stimulated production of inositol phosphates was not affected by the addition of GDP beta S. GTP gamma S, an agonist of G-proteins, largely enhanced the vasopressin- and bombesin-stimulated hydrolysis of inositol lipids when added at 10-100 microM. In the presence of GTP gamma S, the PDGF-stimulated hydrolysis of inositol lipids was not enhanced, but was reduced: 100 microM GTP gamma S reduced the stimulated hydrolysis to about a half of the control level. Only GTP gamma S, and no other nucleoside triphosphates, was found to have these effects. Activation of G-proteins in WFB cells by fluoroaluminate resulted in the inhibition of inositol phosphate production elicited with not only PDGF, but also with vasopressin and bombesin. These results indicate that a G-protein couples vasopressin and bombesin receptors to the activation of phospholipase C. Moreover, these results suggest that coupling of the PDGF receptor to phospholipase C is not mediated through a G-protein.(ABSTRACT TRUNCATED AT 400 WORDS)

Aluminum↗
PubMed1988

Pseudomonas aeruginosa cytotoxin stimulates secretion of amylase and protease zymogens with a concomitant decrease of mRNA levels in isolated rat pancreatic acini.

The action of Pseudomonas aeruginosa cytotoxin on isolated pancreatic acini was investigated. The release of amylase and serine protease zymogens from the isolated rat pancreatic acini was induced with increasing amounts of cytotoxin in vitro. The stimulated release of amylase reached 30% of total cellular content with 100 micrograms/mL of the purified cytotoxin. The induced release of amylase, trypsinogen, proelastase, and chymotrypsinogen reached the maximum after 75 minutes of incubation while lactate dehydrogenase began to appear after 15 minutes of incubation with a secondary biphasic increase at 75 min of incubation. The concentrations of acinar mRNAs of amylase, trypsinogen, proelastase, and chymotrypsinogen, as measured by dot-blot hybridization with the cloned cDNAs of amylase, trypsinogen I, proelastase II, and chymotrypsinogen B of the rat, decreased with time and were significantly lower than in the untreated acini. It is concluded that cytotoxin stimulates the release of amylase and protease zymogens with a concomitant increase in membrane permeability and a decrease of cellular mRNA levels. The inhibition of gene expression is attributable merely to a generalized toxic effect upon cellular metabolism.

Amylases↗
PubMed1988

Role of a guanine nucleotide-binding regulatory protein in the hydrolysis of phosphatidylinositol 4,5-bisphosphate in a human T cell line.

The CD3(T3)/antigen receptor complex appears to function by transducing an antigen signal presented by macrophages into the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. In order to find out how the CD3/antigen receptor complex regulates the hydrolysis of PtdIns(4,5)P2 to diacylglycerol and inositol trisphosphate, we investigated the possible role played by a guanine nucleotide-binding regulatory protein in PtdIns(4,5)P2 hydrolysis in a human T cell leukemia line, JURKAT. JURKAT cells were made permeable to Al3+, F-, GTP, and a nonhydrolyzable GTP analogue, guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S), by treatment with pseudomonal cytotoxin. In the presence of AlCl3 NaF stimulated the release of inositol phosphates in the cytotoxin-treated JURKAT cells. NaF plus AlCl3 induced increases in inositol tris-, bis-, and mono-phosphates and decreases in PtdIns(4,5)P2, phosphatidylinositol 4-phosphate, and phosphatidylinositol within 5 min after addition to the cytotoxin-treated cells at 37 C. GTP gamma S stimulated, to some extent, polyphosphoinositide hydrolysis in the cytotoxin-treated JURKAT. The cytotoxin-treated JURKAT cells retained the ability to respond to anti-Leu-4 with polyphosphoinositide hydrolysis. It has been shown that Al3+ in the presence of F- modulates the activity of various guanine nucleotide-binding regulatory proteins. Therefore, the results obtained in this study indicate that a guanine nucleotide-binding regulatory protein regulates the polyphosphoinositide breakdown in JURKAT cells by influencing phosphodiesterase activity.

Cell Line↗
PubMed1988

Bacterial exotoxins and endothelial permeability for water and albumin in vitro.

Effects of Staphylococcus aureus alpha-toxin and Pseudomonas aeruginosa cytotoxin on the permeability of an endothelial monolayer were studied. Porcine pulmonary artery endothelial cells were grown on a polycarbonate membrane, mounted in a chamber, and exposed to a continuous hydrostatic pressure of 10 cmH2O. On application of this trans-endothelial pressure, endothelial monolayer became "sealed," i.e., the filtration rate for water decreased and the reflection coefficient for albumin increased, reaching a plateau after 1-2 h. Sealed monolayer had a hydraulic conductivity of 2.1 X 10(-6) cm.s-1.cmH2O and an albumin reflection coefficient of 0.73. Permeability of the monolayer was increased on addition of an excess of EDTA and reversed on readdition of calcium. Within 60-90 min after addition of 1 microgram/ml alpha-toxin, the filtration rate increased 75-fold, and the albumin reflection coefficient dropped to 0.20. These changes in permeability were accompanied by cell retraction and formation of large intercellular gaps between endothelial cells. Effects of alpha-toxin were abolished by preincubation with neutralizing antibodies and by inhibitors of calmodulin function. Pseudomonas aeruginosa cytotoxin (25 and 50 micrograms/ml) also increased the permeability of the endothelial monolayer, but it was only about one-third as effective as alpha-toxin.

ADP Ribose Transferases↗
PubMed1988

Cariogenicity of traditional African foodstuffs (maize, beans, sorghum, brown bread) on rat caries.

The cariogenicity of the following traditional African foods was tested in a rat model system: cooked maize and beans, cooked maize and spinach, uncooked and cooked sorghum, both plus 20% sucrose and brown bread, as well as a control (wheat starch plus 50% sucrose). Plaque extent was low in all the test groups and caries incidence was almost zero in all groups except for the cooked wheat starch and 50% sucrose group. Comparison to earlier results suggests a possible cariostatic effect of sorghum but not for the other traditional foods.

Animals↗
PubMed1988

[The pharmacokinetics of common chemotherapeutic drugs used in veterinary medicine].

The present paper summarizes the pharmacokinetics of chemotherapeutic agents commonly used in controlling bacterial disease in animals. Data on absorption, distribution and excretion of chemotherapeutic agents are given in form of tables. It is explained that pharmacokinetic parameters of antimicrobial chemotherapy among others are influenced by the drug's pharmaceutical formulation, its route of administration, its biotransformation and also by the age of the patients. There are given hints for handling the drug in order to achieve optimal effects.

Age Factors↗
PubMed1988

[The connections between structure, pharmacokinetics and effects of glucocorticoids].

Corticosteroids above all have an influence on the metabolism of proteins, lipids and carbohydrates. Inflammatory and immunological reactions are suppressed. The effects are based on the induction of both primary and secondary responses. Examples in catabolic and anabolic reactions are described. The significance of bioavailability is illustrated and hints to discriminate the types of corticosteroids for therapeutic requirement are given.

Animals↗