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Biomedical subjects

G Laber

Publications and source records attributed to G Laber.

At least 37 records · Page 2Linked to original sources
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

Opsonic activity of the alternative complement pathway in infected human intra-abdominal fluid.

The complement-mediated opsonic activity (CMOA) in intra-abdominal exudates collected during laparotomy from peritonitis patients was examined by an in vitro phagocytic bactericidal assay. It was found that infected intra-abdominal exudates barely promoted detectable killing of Escherichia coli 01 by polymorphonuclear leukocytes. Only the minority of bacteria recovered by differential centrifugation from the infected exudates had C3 on their surfaces. Such bacteria were not optimally opsonized in vivo, whereas they became fully coated with C3 during a brief incubation in vitro in normal human serum. The low level of CMOA in the peritoneal fluid paralleled a depletion of complement in the peripheral blood. Thus, in cases complicated by sepsis with gram-negative bacteria, the CMOA in the blood was extremely low. These data suggest that the high susceptibility of the peritoneum to infection by gut flora, despite the normal phagocytic response, may be partly explained by the low local level of functional complement which is inadequate for optimal opsonization of the bacteria.

Adult↗
PubMedDate not supplied

The effect of aging on laboratory values in dogs.

The main objective of this study was to examine age-associated changes in laboratory values in dogs in order to establish standard values for dogs of a certain age. These standard values could serve to judge the health status of individual dogs and possibly estimate their remaining life expectancy. Thus, haematological and immunological parameters, plasma constituents, kidney characteristics and the capacity of homeostasis were determined in German shephard dogs (0.5-13.5 years) and beagles (4-9 years). Significant changes were noted. We detected that the number of white blood cells declines with age. The change in a number of organ specific enzymes indicates organ involution and increased cell death. Increased plasma glucose levels and a decreased glucose tolerance point to a diminished sensitivity of tissue to concentrations change due to a decrease in organ production and changes in the immune system, which are also reflected in an impaired lymphocyte proliferation capacity. These factors lead to an increased blood sedimentation rate. Cortisol increases might reflect a reduced stress resistance. Age-related decreases in aldosterone concentration and PAH-clearance were also found.

Aging↗