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Biomedical subjects

G Laber

Publications and source records attributed to G Laber.

18 recordsLinked to original sources
PubMed1990

Bronchoalveolar lavage in dogs; analysis of proteins and respiratory cells.

In an attempt to establish the normal values, bronchial alveolar lavage (BAL) of portions of the right upper lobe was done during fiberoptic bronchoscopy in 18 Beagle dogs of various ages. Albumin, IgA and IgG were identified in BAL fluids. The respiratory cells obtained were, in the order of decreasing occurrences, alveolar macrophages, lymphocytes, epithelial cells and neutrophils. No age-related changes were found in the content of immunoglobulins or in the differential cell counts of respiratory cells. Bacterial cultures of BAL were invariably contaminated with resident flora of the upper respiratory tract. Therefore, in determining the etiology of pulmonary infections, the results of such cultures should be interpreted with caution. As an aid to diagnosis of pulmonary diseases in dogs, the analysis of BAL fluid components could be helpful when compared with findings in healthy animals.

Albumins↗
PubMed1989

Epizootiological examination of a respiratory disease associated with mycoplasma infection in horse.

The authors examined 585 samples from 92 mares of 2 studs and 346 nasal swabs taken from their foals for the presence of mycoplasmas. The positive rates of mares and foals were 81.5% and 71.7%, respectively, with positivity of samples being variable. Clinical symptoms developed in 2-4 waves and lasted 3-7 days, with intervals of 7-12 days. The disease started in April among foals born in February, at an average age of 88 days. Later on, the average age of the affected foals decreased. There was a correlation between presence of mycoplasmas in nasal cavity and disease of foals.

Animals↗
PubMed1979

Experience with testing for mycoplasma with five different methods.

Five methods for mycoplasma-content detection in cell-cultures are established in this laboratory. Results with about 20 different cell lines continuously grown in this laboratory in some determinations indicate that four methods give good correspondence. A microbiological method gave contrary results in many cases. It is possible that new infections will grow on mycoplasma broth but the older infections are adapted to cell-culture and give negative results on artificial medium. New low-level infections cannot be detected by the other methods which do not include any efficient enrichment step. The most convenient method in our opinion is a DNA-staining method according to Chen because this is a very quick, inexpensive and easily performable process. In practice it seems necessary to check cell cultures in two ways, firstly with a quick method and additionally with the microbiological test to ensure the detection of new low-level infections.

Animals↗
PubMed1978

In vitro activity of tiamulin (81.723 HFU), a new pleuromulin derivative, against clinically significant anaerobes.

The susceptibility of more than 40 strains of Gram-negative and Gram-positive anaerobes to tiamulin (Sandoz 81.723 hfu), a new pleuromulin (pleuromutilin) derivative, was determined by broth dilution and agar dilution tests. The influences of density of the inoculum upon MICs was studied by a specially designed pour plate-technique. Bacteroides fragilis, B. vulgatus, B. splanchnicus, B. oralis, B. asaccharolyticus, B. melaninogenicus, Fusobacterium fusiforme (F. nucleatum), Sphaerophorus necrophorus, Clostridium perfringens, C. fallax, Propionibacterium acnes and several species of Peptococcaceae showed broth dilution MICs of 0.03 similar to 1 microgram/ml. Members of B. thetaiotaomicron, B. distasonis and S. freundii (F. mortiferum) were inhibited by 8 similar to 32 microgram/ml and 2 strains of S. varius had a broth dilution MIC of 256 microgram/ml. With most strains, the agar dilution MICs were 2 similar to 4 similar to 8 times the broth dilution MICs. In pour plate-tests, the MICs were not considerably influenced influenced by varying initial concentrations of viable cells. With most anaerobes, the MBCs of tiamulin were more than 100-fold higher than the MICs. The results obtained indicated that, apart from S. varius, B. thetaiotaomicron, B. distasonis and S. freundii (F. mortiferum), members of 16 other anaerobic species including B. fragilis were without exception sensitive to tiamulin.

Anti-Bacterial Agents↗
PubMed1977

Prophylactical and therapeutical efficacy of Tiamuline in mycoplasmosis of chickens and turkeys.

To evaluate efficacy of Tiamuline in mycoplasmosis of chickens and turkeys under controlled field conditions 2 prophylactical and 3 therapeutical trials were conducted. The compound was administered via drinking water for 3 days in comparison to Tylosin tartrate. In both prophylactical and therapeutical tests, Tiamuline showed a superior efficiacy, as measured by clinical symptoms, pathological lesions and microbiological findings. Therefore, Tiamuline can be recommended for treatment of mycoplasmosis in chickens and turkeys in a dosage of 0.025% and in a dosage of 0.0125% for prophylaxis in flocks at risk.

Animals↗
PubMed1977

Blood level studies in chickens, turkey poults and swine with tiamulin, a new antibiotic.

Tiamulin concentrations have been determined in the serum of chickens, turkeys and swine after a single oral administration of various doses. The compound peaked between 2 and 4 hours after drug supply. In the highest dose used (50 mg/kg body weight), mean concentrations of 3.5, 2.9, 4.5 microgram/ml for chickens, turkeys and swine, respectively, could be obtained. In poultry, the levels declined between 12 and 24 hours to values not useful for calculation. In swine at 24 hours after administration measurable values could still be detected.

Administration, Oral↗
PubMed1977

[In vitro and in vivo activity of tiamulin against leptospires (author's transl)].

The minimal growth inhibiting concentration of tiamulin, a derivative of the diterpen antibiotic pleuromutilin, was evaluated in vitro against 11 different serogroups of leptospira interrogans by twofold serial dilution technique, in comparison to tetracyclin, dihydrostreptomycin and tylosin. The range of the MIC values of tiamulin is between 0.07 and 2.5 microgram/ml and thus comparable to the activities of the standard antibiotics tested (see table 1). The chemotherapeutic efficacy (ED50) of the compound was examined in two experimental leptospiral infections of the Syrian hamster, in comparison to tetracyclin. Both compounds were administered orally for 3 days. In the L. canicola infection, the ED50 values were 103.8 mg/kg and 306.3 mg/kg body-weight for tiamulin and tetracyclin, respectively. In the L. grippotyphosa infection, the ED50 values amounted to 35.16 and 277.5 mg/kg bodyweight for tiamulin and tetracyclin, respectively. Based on these values, tiamulin in comparison to tetracyclin showed 3-8 fold higher efficacy in vivo after oral administration.

Animals↗
PubMed1976

[Clinical and histopathological findings in mycoplasmal polyarthritis of rats. III. Course of infection during the weeks 7-30 and 54-61 (author's transl)].

Clinical, microbiological and histological findings of the late phase of experimentally induced Mycoplasma-polyarthritis in rats are described. Investigations were carried out between the 7.-30. week and between the 54-61. week p.i. M. arthritidis could be reisolated from affected joints regularly up to the 7th week p.i. Thereafter until 12th week only occasional recovery was possible. The healing process of affected joints dominated signs of arthritis which could be confirmed histologically as a purulent process. The alterations of carpal and tarsal joints were divided into purulent, chronic deforming and chronic minor lesions. The findings derived from investigation of joints and parenchymatous organs during the course of the disease are discussed.

Animals↗
PubMed1975

Antimicrobial activities of 81.723 hfu, a new pleuromutilin derivative.

The new pleuromutilin derivative 81.723 hfu is extremely active against gram-positive organisms such as streptococci, staphylococci, and against mycoplasmas. A number of Shigella, Klebsiella, and Escherichia coli strains were also found to be quite susceptible to this new agent, whereas other gram-negative organisms like Pseudomonas aeruginosa, Proteus species, and Alcaligenes faecalis proved to be naturally resistant to 81.723 hfu. The new compound acts bacteriostatically. Bactericidal effects have been observed only at concentrations which are 100-fold higher than the minimal inhibitory concentrations. The new antibiotic is well tolerated in all animal species tested so far and has been successfully used in the treatment of experimental infections with gram-positive organisms and with mycoplasmas in mice and rats. Resistance against this new compound arose gradually in all microorganisms investigated. It is noteworthy that the rate at which resistance against 81.723 hfu emerged in mycoplasmas (Mycoplasma gallisepticum and Mycoplasma hyorhinis) was significantly slower than the corresponding rate at which resistance against tylosin tartrate appeared. Mycoplasma strains which became insensitive to 81.723 hfu were also resistant to tylosin tartrate, whereas mycoplasmas which developed resistance against tylosin tartrate, although less sensitive to 81.723 hfu than wild-type strains, were still eliminated by this drug. In a strain of Klebsiella pneumoniae, complete cross-resistance was observed between the pleuromutilin derivative on one hand and lincomycin and erythromycin on the other. Modest degrees of cross-resistance were also observed with chloramphenicol. However, it appears unlikely that the latter phenomenon is sufficiently pronounced to affect treatment with either antibiotic.

Agaricales↗
PubMed1975

In vivo efficacy of 81.723 hfu, a new pleuromutilin derivative against experimentally induced airsacculitis in chicks and turkey poults.

The efficacy of the pleuromutilin derivative 81.723 hfu was tested in chicks and turkey poults by experimentally infecting them with Mycoplasma gallisepticum. The data were treated to obtain the mean effective doses, and these were compared to those obtained with tylosin tartrate. The compounds were administered either by ingluvial catheter or via the drinking water. Therapy was started on the day of inoculation or 7 days thereafter, respectively. The experiments showed that the compound 81.723 hfu was significantly more active in chickens than tylosin tartrate by both methods of administration of drinking water. In turkey poults the pleuromutilin derivative and tylosin tartrate had comparable activity.

Air Sacs↗
PubMed1975

[Clinical and histopathological findings in mycoplasmal polyarthritis of rats. I. Course of infection during the first 8 days (author's transl)].

Polyarthritis in rats could be induced by intraperitoneal infection with M. arthritidis. The mycoplasma culture alone or in combination with infusorial earth was used as inoculum. The histopathological changes consisted of initial lesions in the transitional zone of the articular capsule which could be attributed to disturbances of vascular permeability. After two days suppurative arthritis occurred, which was accompanied by massive inflammatory lesions of the articular capsule and of the periarticular tissues. Towards the end of the observation period erosions of cartilage, pannus formation and periarticular foci of purulent necrobiosis were found. Especially the synovial membrane was subjected to profound changes and dense cellular infiltration. The cell infiltration, mesenchymal proliferation and changes of vascular permeability showed variations in timing and degree depending on the modi of infection. The histological examinations of organs indicated generalization of the infection.

Animals↗
PubMed1975

[Clinical and histopathological findings in mycoplasmal polyarthritis of rats. II. Course of disease between the 2. and 6. week (authors transl)].

Between the 9th and 42nd day p.i. the clinical features and microbiological findings of rats infected intraperitoneally with mycoplasma arthritidis were recorded and a histological investigation was carried out. From the 12th day p.i. arthritic lesions clinically showed a gradual regression. Until the 42nd day p.i. mycoplasmas and purulent exudate were present within the joint cavity. During the course of infection a gradual increase of mesenchymal cell activity was found, leading to the formation of considerable amounts of secondary synovialis. Between the epiphysis the pannus formed tissue laces, which after the 3rd week p. i. showed sequestration. During the further course of disease an increased number of focal plasma cell accumulations was observed within the joint capsule. Partial erosions of hyaline cartilage, especially near its edge, could frequently be seen. Within the cellular exudate of the joint cavity the number of macrophages steadily increased whereas remmants of exudate were mainly located in the recesses of the joint capsule. In the periarticular tissue, cellular infiltration, mesenchymal cell proliferation and purulent necrotic foci were present. In the supporting osseous tissues osteomyelitis, abscesses, periosteal new bone formation and the occurrence of mosaic bone could be observed. The lesions found in spleen and lymph-nodes indicated the persistence of a systemic reaction within the RES.

Animals↗
PubMed1975

[Hematological investigations in rats experimentally infected with m. arthritidis (author's transl)].

Hematological investigations were carried out regularly during the course of an experimental M. arthritidis-infection in rats. The alterations observed in the peripheral blood were essentially those usually found in infections. In addition, a moderate thrombocytosis and a depression of the parameters of the red blood count could be seen. In lymphnodes and spleen phagocyting RES-cells were increased 4 days post inoculationem (p.i.) and vacuolized makrophages could be observed 7 days p.i. On the 10. day p.i. very immature cells could be seen in these organs, morphologically resembling hemohistioblasts. Mature cells as well as precursors of this type of cell were found to be increased 2-3 weeks p.i. Bone marrow and thymus have been found normal during the whole period of investigation.

Animals↗
PubMedDate not supplied

Simultaneous treatment of chickens with salinomycin and tiamulin in feed.

Laboratory and field experiments involving more than 100,000 birds were performed to assess the effect of simultaneous in-feed medication of chickens with salinomycin and tiamulin at various concentrations. In an artificial infection study with Mycoplasma gallisepticum, low levels of tiamulin (10-40 ppm) did not induce signs of ionophore intoxication with salinomycin at 60 ppm in the feed, whereas levels of 50 ppm caused early signs with a mild growth depression. A level of 20 ppm gave a maximum average improvement in growth rate of 12.5%. There was a dose-related response in mycoplasma lesion inhibition, with 50 ppm reducing lesions by 75%. In the two field trials, chickens suffering from mycoplasmosis complicated with infectious bronchitis and receiving 60 ppm salinomycin in the feed showed marked improvements in mortality rates, lesion scores, and feed-conversion efficiency when tiamulin was added at 20 ppm and 30 ppm in the feed. There were no signs of incompatibility between the two antibiotics at these levels.

Administration, Oral↗