Search PubMed⌕ Search

Biomedical subjects

H Werner

Publications and source records attributed to H Werner.

At least 145 records · Page 8Linked to original sources
PubMed1990

[Electrochemical examinations of influence of mechanical treatment of surfaces on the corrosion of different dental amalgams. 1. Potential and corrosion rate and breakdown potential].

In a cell with artificial saliva the electrochemical behaviour of amalgam specimens of Germadent, Duragam and ANA 2000 is analysed in dependence of the surface treatments carving, burnishing and polishing using potentiodynamic polarization with low polarization rate. The less roughness and content of gamma-2-phase the better the amalgam reacts to corrosion evident in a higher potential, a lower corrosion rate and a higher breakdown potential. Foremost the polish supplies the best resistance to corrosion. Duragam-amalgam is more resistant than Germadent-amalgam. Polished specimens of Duragam react likely specimens of ANA 2000.

Corrosion↗
PubMed1989

Optimization and in situ detection of Escherichia coli beta-galactosidase gene expression in Dictyostelium discoideum.

We show that a fusion gene, containing the promoter and 5'-noncoding region of a Dictyostelium discoideum actin 6 gene linked to the Escherichia coli beta-galactosidase (beta Gal) gene (lacZ), directs the production of functionally active beta Gal in D. discoideum and that the enzyme can be detected by staining in situ; a procedure which will be of great value in analyzing cell-type-specific gene expression. We illustrate this by fusing lacZ to the promoter of the prespore-specific gene, D19, and localizing expressing cells in migrating slugs. Optimal expression requires the inclusion of termination and polyadenylylation signals and we describe pDDlac, a vector containing a multiple cloning site upstream from a lacZ-Dictyostelium terminator fusion, which can be used to analyze regulated promoters.

Amino Acid Sequence↗
PubMed1989

[Susceptibility of clinically important Bacteroides species against enoxacin-metronidazole and enoxacin-clindamycin combinations].

To assess the activity of enoxacin, clindamycin and metronidazole, MICs of clinical isolates of saccharolytic intestinal Bacteroides spp. were determined, using the agar dilution method according to NCCLS guidelines. Checkerboard titrations of enoxacin-metronidazole and enoxacin-clindamycin were done on Wilkins-Chalgren agar; inoculation, incubation and reading of plates were as for determination of MICs. Metronidazole MIC 90s for Bacteroides fragilis (23 strains) and Bacteroides thetaiotaomicron (23 strains) were 0.5 mg/l, clindamycin MIC 90 for B. fragilis was 1 mg/l, and for B. thetaiotaomicron 8 mg/l, whereas enoxacin MIC 90 values were 16 mg/l and 64 mg/l, respectively. The evaluation of the inhibitory effects of the combination enoxacin-metronidazole for B. fragilis showed additional effects in eleven strains, indifference in seven strains and antagonism in one. The figures for B. thetaiotaomicron showed addition in five strains, indifference in 17 strains, antagonism in one. For B. fragilis the combination enoxacin-clindamycin showed addition in ten strains, indifference in six, and antagonism in one; for B. thetaiotaomicron synergism in one strain, addition in four strains, indifference in 17 strains. In conclusion, the absence of antagonism and the overall preponderance of additional and indifferent effects warrant the use of enoxacin in combination with metronidazole or clindamycin in clinical trials of treatment of anaerobic-aerobic mixed infections.

Bacteroides↗
PubMed1989

Estrogen regulation of vasoactive intestinal peptide mRNA in rat hypothalamus.

The participation of gonadal steroid hormones in regulation of the vasoactive intestinal peptide (VIP) gene expression in the hypothalamus was studied using a quantitative densitometric hybridization assay. In the female rat the levels of VIP mRNA were found to be significantly decreased following ovariectomy (4.41 +/- 0.7 arbitrary units of absorbance vs. 8.52 +/- 0.18). This decrease was largely reversed after three days of treatment with estradiol dibenzoate. In contrast to the female rats, no significant change in VIP mRNA levels was observed in the male rats, following orchidectomy. These results suggest a sexual dimorphism with regard to the steroid regulation of hypothalamic VIP gene expression in the rat.

Animals↗
PubMed1989

A multicenter international study on the activity of sulbactam/ampicillin, ampicillin, and cefoxitin against anaerobic bacteria and introduction of a new model of susceptibility testing in mixed infections.

Susceptibility of anaerobic clinical isolates from the United States, Canada, and Germany to sulbactam/ampicillin (1 + 2) (SBT/AMP), ampicillin alone (AMP), and cefoxitin (CFX) was determined with a standard agar dilution test. The isolates included 192 strains of Bacteroides fragilis, 132 strains of other Bacteroides spp., and 19 strains of Clostridium spp. Against all species tested, SBT/AMP was more active than AMP or CFX. Results obtained by a new model of associative susceptibility testing indicated that susceptibility testing of single pathogens from polymicrobial infections is not necessarily reflective of the susceptibility of the pathogens at the site of infection. The results suggest that sulbactam is effective in associations of pathogens producing beta-lactamases of Richmond-Sykes types II-V and beta-lactamases of anaerobic bacteria.

Ampicillin↗
PubMed1989

GasPak Plus versus Anaerocult A--two carbon dioxide/hydrogen systems for cultivation of anaerobes.

Two disposable carbon dioxide/hydrogen gas-generating systems (GasPak Plus and Anaerocult A) were compared by assessing growth of obligate anaerobic bacteria. Eighty strains representing 28 species of anaerobic bacteria commonly occurring at various body sites were seeded onto 4 brain heart chocolate agar plates using a spiral plater; and 1 plate each was subsequently incubated in 2 Anaerocult A and 2 GasPak Plus systems. Bacterial growth was expressed as colony-forming units per ml (CFU/ml), reproducibility of the seeding procedure was checked, and the potential interference of H2S-producing bacteria with operation of the carbon dioxide/hydrogen systems was investigated. The presence of H2S only inhibited bacterial growth in the case of Peptostreptococcus asaccharolyticus - an effect observed in both systems. Reproducibility of the seeding procedure using the spiral plater was within acceptable range. Differences between the systems were not apparent when comparing total CFU/ml of a given species and the systems therefore provide equally effective environments for incubation of anaerobic bacteria. In both systems, however, growth varied from one species or strain to another. In mixed infections, detection of certain species of anaerobes may therefore be difficult using either system.

Bacteria, Anaerobic↗
PubMed1989

Developmental regulation of the rat insulin-like growth factor I receptor gene.

We have investigated the developmental regulation of the rat insulin-like growth factor I (IGF-I) receptor gene in various tissues using a sensitive and specific solution hybridization/RNase protection assay. For this purpose we characterized rat IGF-I receptor cDNAs that were cloned from a simian virus 40-transformed rat granulosa cell cDNA library. The specific cDNA clone used in these studies encoded the putative signal peptide and the first 53 amino acids of the alpha subunit and was approximately 94% homologous to its human counterpart. IGF-I receptor gene expression was studied during the perinatal period and at various intervals until early adulthood. Overall, steady-state IGF-I receptor mRNA levels decreased dramatically during postnatal development; however, the extent of the decrease differed among the various tissues studied. In contrast to receptor mRNA levels, IGF-I mRNA levels increased in some of the same tissues. The molecular mechanisms underlying this apparent divergent transcriptional control of the IGF-I and IGF-I receptor genes warrant further study.

Amino Acid Sequence↗
PubMed1989

Efficacy of clavulanate-potentiated antibiotics against Bacteroides species and artificially associated cultures of aerobes and anaerobes.

Clavulanic acid is known to potentiate the activity of amoxycillin and ticarcillin against beta-lactamase-producing Bacteroides species. In order to assess the usefulness of the clavulanate antibiotics in mixed infections with aerobes and anaerobes, artificially associated cultures of clinically significant Bacteroides species and facultative anaerobes (Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, Enterococcus faecalis, Staphylococcus spp. and Streptococcus spp.) were tested. The minimal bactericidal concentrations (MBC) of amoxycillin and ticarcillin, singly and in combination with clavulanate, were determined for the individual species in the associated culture and for the associated culture as a whole. In the absence of clavulanate, association experiments showed that the MBCs of susceptible strains increased in the presence of beta-lactamase-producing species, whereas the addition of clavulanate to the test systems led to MBCs which were mostly comparable to values as determined in single strain testing.

Bacteria, Aerobic↗
PubMed1989

Regulation by fasting of rat insulin-like growth factor I and its receptor. Effects on gene expression and binding.

We have examined, in liver and extrahepatic tissues, the effects of fasting on total insulin-like growth factor I (IGF-I) mRNA levels, on levels of different IGF-I mRNAs generated by alternative splicing of the primary IGF-I transcript, and on IGF-I receptor binding and mRNA levels. A 48-h fast decreased total IGF-I mRNA levels by approximately 80% in lung and liver, approximately 60% in kidney and muscle, and only approximately 30-40% in stomach, brain, and testes. In heart, IGF-I mRNA levels did not change. The levels of the different splicing variants, however, were essentially coordinately regulated within a given tissue. Specific 125I-IGF-I binding in lung, testes, stomach, kidney, and heart was increased by fasting by approximately 30-100%, whereas in brain 125I-IGF-I binding did not change in response to fasting. In tissues in which fasting increased IGF-I receptor number, receptor mRNA levels increased approximately 1.6- to 2.5-fold, whereas when IGF-I receptor number was unchanged in response to fasting, receptor mRNA levels did not change. These data demonstrate that the change in IGF-I and IGF-I receptor mRNA levels during fasting is quantitatively different in different tissues and suggest that regulation of IGF-I and IGF-I receptor gene expression by fasting is discoordinate.

Animals↗
PubMed1989

Regulation of rat brain/HepG2 glucose transporter gene expression by insulin and insulin-like growth factor-I in primary cultures of neuronal and glial cells.

We have demonstrated the expression of the rat brain/HepG2 glucose transporter gene in primary cultures of rat neuronal and glial cells by Northern blot analysis with a rat brain glucose transporter cDNA probe. Incubation of both neuronal and glial cells with insulin and insulin-like growth factor-I induced a time- and dose-dependent increase in the steady state levels of glucose transporter mRNA. The maximal response was achieved between 2-4 h and subsequently decreased. Both insulin and insulin-like growth factor-I at a dose of 1 ng/ml elicited an approximately 57% increase in glucose transporter mRNA levels in neuronal cultures after 90 min, suggesting that each peptide was acting through its own receptor. On the other hand, insulin stimulated [3H]2-deoxyglucose uptake in glial, but not neuronal, cells. These results suggest that insulin-like peptides regulate the expression of the rat brain/Hep G2 glucose transporter gene at both transcriptional and posttranscriptional levels, and that these regulatory mechanisms may be dissociated from each other. Insulin-like peptides may, therefore, participate in the control of brain energy metabolism.

Animals↗
PubMed1989

Developmental regulation of rat brain/Hep G2 glucose transporter gene expression.

The developmental regulation of rat brain-derived/Hep G2 glucose transporter gene expression was studied by means of Northern blot hybridization, using a rat brain glucose transporter cDNA probe, in order to directly quantify steady state glucose transporter mRNA levels. The results obtained showed different tissue-specific patterns of glucose transporter mRNA levels during ontogenesis; while in brain there was a sustained increase in the levels of the message from 20 days embryogenesis until 50 days postnatal, other organs such as heart, lung, liver, and muscle expressed maximal levels of the glucose transporter mRNA in 20-day fetuses and 1-day neonates, decreasing subsequently to very low levels. The relative expression of the glucose transporter mRNA in the different tissues, at both fetal and adult stages, was analyzed using a solution hybridization-RNase protection assay. This approach revealed that, while the heart expresses the highest levels of glucose transporter mRNA at 20 days of fetal life, the brain shows the highest levels at the adult stage. These results indicate a tissue-specific ontogenic pattern of glucose transporter gene expression, suggesting a developmental role for this glucose transporter gene product.

Animals↗
PubMed1989

Influence of substance P and substance P--sequences on immunocompetent cells.

The influence of substance P (SP) and substance P-sequences on spleen cell cultures of mice and on rat lymph node mononuclear cells was studied. SP and the N-terminal fragments SP(1-4) and SP(1-7) were capable of inducing the secretion of lymphokines with chemotactic properties for polymorphonuclear leukocytes and lymphocytes. The peak of the dose-response curves appeared in a concentration range of 10(-11) to 10(-10) mol/l. The predominant migratory stimulatory activity was found at a molecular mass of 12,000 and 23,000 dalton and an inhibitory activity at 35,000 dalton. The C-terminal part of the peptide, SP(6-11), SP(7-11), SP(8-11), SP(9-11), was not able to induce such lymphokine secretion. The experimental results display the importance of the N-terminal fragment for the lymphokine secretion, and support the hypothesis that SP is also a peptide with modulatory functions in the immune response.

Animals↗
PubMed1989

[Correlation of complement activation, cytokine liberation and beta 2 microglobulin in the use of various dialysis and hemofiltration membranes].

The release of biological active factors from blood cells, e.g. interleukin 1, is of importance with regard to the bioavailability testing of membranes for extracorporeal blood purification. The data from an in vitro system of cytokine release may show a connection between complement activation and cytokine (interleukin) release of membranes. In contrast the results of the generation rate of beta 2-microglobulin did show no definite reference to complement activation or cytokine release. Further time-dependent investigations of the generation rate beta 2-microglobulin are necessary.

Biocompatible Materials↗
PubMed1989

[Attitude and sex behavior following hysterectomy].

488 women have been asked after abdominal or vaginal hysterectomy by way of retrospective questionnaires about preoperative anxieties, postoperative psychosomatic complaints as well as disturbances of their vita sexualis. 48.6% of the patients had anxieties before operation and anaesthesia. After hysterectomy 71.9% of the women reported about hot flushes and other psycho-vegetative complaints. Although hot flushes occurred significantly more frequent in patients with salpingooophorectomy they could be observed also in one third of the women without removal of the ovaries. However libido, cohabitation frequency and orgasm ability were reduced significantly more frequent in the group of women after hysterectomy with salpingooophorectomy. This is caused by the failing blood supply to the ovary via the branches of the uterine artery. The reduce postoperative psychosomatic complaints as well as sexual dysfunctions it is important to give qualited instructions before and after the operation. On no account should a prophylactic exstirpation of the adnexa be carried out before the age of 50 years. A hormonal substitution is recommended to be done in time even for patients whose ovaries have not been removed suffering from psycho-somatio discomforts.

Adult↗