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Biomedical subjects

D Hartmann

Publications and source records attributed to D Hartmann.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Unusual course of malignant synovioma of the flexor tendon sheath of the hand].

The authors report a synovial sarcoma of the hand with an unusual case history and a favorable outcome after two years. A forty-four-year old woman suffering from uncharacteristic pain in the right hand with slightly abnormal EMG-findings for the median nerve was treated by operative release of the carpal tunnel. No unusual findings were discovered intraoperatively. The patient continued suffering from disabling pain for another year so that a second operation was performed by another surgeon. He discovered a tumor behind the median nerve which could not be removed radically because of profuse bleeding. In spite of diagnosing a sarcoma, the patient refused further surgery, however combined radio- and chemotherapy was administered for one year. The tumor was reduced in size but did not disappear. Following open biopsy and proved presence of sarcoma, the remaining tumor was removed by amputating the ulnar part of the hand. Two years following this last operation, the patient is free of local symptoms and there is no evidence of metastases.

Adult↗
PubMed1989

The pharmacology of reversible monoamine oxidase inhibitors.

The older monoamine oxidase inhibitors (MAOIs) are mechanism-based, irreversible inhibitors of MAO; most inhibit both the A and B forms of MAO. Several of the drugs are hydrazine derivatives which have non-specific effects other than MAO inhibition. These properties convey disadvantages, which may be seen as serious, though infrequent, adverse events--the 'cheese effect', hepatotoxicity, amphetamine-like activity, orthostatic hypotension and anticholinergic effects. New, reversible MAOIs stem from a variety of chemical classes and are more specific in their effects, with relatively rapid onset of action, direct relationship between plasma concentration and pharmacological effect, and no prolonged carry-over phenomena.

Administration, Oral↗
PubMed1988

Interleukin-1 alpha modulates collagen gene expression in cultured synovial cells.

The effects of porcine interleukin-1 (IL-1) alpha on collagen production were studied in cultured human rheumatoid synovial cells. Addition of 0.05-5 ng of IL-1/ml into the cultures resulted in a dose-dependent decreased rate of collagen released into the medium over 24 h. To determine whether this inhibition was due to secondary action of prostaglandin E2 (PGE2) secreted in response to IL-1, cultures were incubated in presence of various inhibitors of arachidonate metabolism. Depending on the cell strains, these inhibitors were able to suppress or diminish the effect of IL-1, suggesting that PGE2 is involved in the mechanism. Depression of collagen production caused by IL-1 mainly affected type I collagen and therefore led to a change in the type I/type III collagen ratio in the extracellular medium. Steady-state levels of mRNA for types I and III procollagens were estimated by dot-blot hybridization and compared with the amounts of respective collagens produced in the same cultures. IL-1 generally increased procollagen type I mRNA, but to a variable extent, as did indomethacin (Indo). Depending on the cell strain, the combination of indo and IL-1 could elevate the mRNA level of type I procollagen compared with Indo alone. These results did not correlate with the production rate of collagen in the medium, which was diminished by exposure to IL-1. The level of mRNA for collagen type III was not greatly changed by incubation with IL-1, and a better correlation was generally observed with the amount of type III collagen found in the medium. These data suggest that an additional control mechanism at translational or post-translational level must exist, counterbalancing the stimulatory effect of IL-1 on collagen mRNA transcription. It is likely that IL-1 could modulate the production of collagen in synovial cells by an interplay of different mechanisms, some of them limiting the effect of primary elevation of the steady-state mRNA level.

Bucladesine↗
PubMed1988

Establishment and characterization of long-term cultured cell lines of murine resident macrophages.

Murine resident macrophages can proliferate in vitro when they are grown in coculture on a layer of mesothelial or endothelial type feeder cells. Resident macrophages were obtained from lung explants of C57Bl/6 lpr/lpr mice and from spleen explants or peritoneal washing of Balb/c mice; the cells were seeded without further washing. After 3-4 weeks of culture, the macrophages began to proliferate on a confluent layer of feeder cells. The macrophages then could be collected in the fluid phase and reseeded for permanent culture after generation of a new feeder layer. These cells were characterized as macrophages by the following criteria: 1) their morphology, ultrastructure, and adherence properties; 2) more than 90% of the macrophages phagocytized yeasts compared with less than 1% of the feeder cells; 3) the presence of functional Fc and mannose receptors, nonspecific cytoplasmic esterases, and membrane ectoenzymes such as nicotinamide adenine dinucleotide (NAD) glycohydrolase and nucleotide pyrophosphatase; 4) by cytofluorographic phenotype analysis with monoclonal antibodies, characterizing a normal macrophage population (MAC1+, Fcrec+, H-2K+, THY1-, LYT2-, L3T4-). 5) by functional studies proving that the expanded macrophages could function as accessory cells in the induction of lymphocyte proliferation in response to concanavalin A (Con A), that they generated reactive oxygen radicals and that they were cytotoxic for tumor cells. During coculture, growth or activating factors such as macrophage colony-stimulating factor or gamma-interferon were released in the medium. Long-term cultured macrophages had chromosomal abnormalities. Our study suggests that tissue macrophages can proliferate in vitro and hence that it is possible to establish long-term cultured cell lines of macrophages of defined and reproducible characteristics.

Animals↗
PubMed1988

Experimental model for the investigation of kinetic and/or dynamic interactions between drugs and ethanol in humans.

This study was performed to establish an experimental method for the investigation of interactions between ethanol and drugs under predictable and controlled conditions. The model was tested with flumazenil (Ro 15-1788), a short-acting benzodiazepine antagonist with an elimination half-life of 1 h. Six healthy volunteers (5 males, 1 female) were administered ethanol by intravenous infusion with stepwise changing rates. The infusion rates were adapted to each subject on the basis of individual disposition parameters of ethanol, which were derived from preceding short-term infusions of 120 min duration (1.0 mg/kg in males, 0.8 mg/kg in the female). This two-step procedure led to individual ethanol plasma levels between 1.47 +/- 0.04 and 1.71 +/- 0.03 g/L, which were reached after 2.5 h and thereafter maintained over another 6 h. Within the period of constant ethanol levels, single doses of flumazenil and placebo, respectively, were injected intravenously as a bolus (2 min) in a double-blind fashion according to a randomized two-way crossover design. Three subjects received a dose of 0.10 mg/kg of flumazenil, and the remaining three subjects received a dose of 0.20 mg/kg. Evaluation of the plasma concentration time curves of flumazenil did not reveal evidence of an effect of ethanol on the pharmacokinetics of this drug.

Adult↗
PubMed1988

Lack of effect of the benzodiazepine antagonist flumazenil (Ro 15-1788) on the performance of healthy subjects during experimentally induced ethanol intoxication.

Flumazenil is a specific benzodiazepine antagonist. This study was designed to determine whether it also reverses CNS depression due to acute alcohol intoxication. Intoxication was experimentally induced in 6 healthy volunteers by intravenous infusion of ethanol. Individual constant ethanol plasma concentrations in the range 1.47 +/- 0.04 g.l-1 to 1.71 +/- 0.03 g.l-1 were maintained over 6 h. Two doses of flumazenil (0.1 or 0.2 mg.kg-1) and placebo were administered intravenously in a randomized, double-blind, two-way cross-over fashion. A battery of psychometric tests and subjective ratings of mood and performance were performed at baseline and at regular intervals during the study. Before the administration of flumazenil the characteristic symptoms and signs of ethanol intoxication were present in all subjects. Performance (measured by visual analogue scales), reaction time, digit symbol substitution test, and a tracing test, were markedly impaired by ethanol. After the injection of flumazenil three volunteers reported some subjective improvement in performance. However, in none of the subjects was there a difference between either dose of flumazenil and placebo in terms of an improvement in the objective psychometric variables.

Adult↗
PubMed1988

Haemophilus influenzae type b septicaemia associated with myonecrosis and thigh abscess.

A case is reported of a male adult with Haemophilus influenzae type b septicaemia and subsequent abscess in the left thigh due to this microorganism following injection of phenylbutazone. The phenylbutazone probably caused muscle cell damage. It is assumed that Haemophilus influenzae type b colonized the site during an episode of septicaemia, with subsequent development of necrosis and abscess.

Abscess↗
PubMed1988

Control of the antitumoral activity of human macrophages produced in large amounts in view of adoptive transfer.

Purified human blood monocytes were grown in hydrophobic bags in RPMI medium containing additional amino acids, indomethacine and growth factors. Autologous serum was added after a few days of culture at 37 degrees C, 5% CO2. The antitumoral activity generated by activated monocytes against human tumor cells grown in vitro was mediated by soluble effectors in contrast to macrophages which acted by cell contact. Monocyte differentiation into macrophages was achieved after 7 days of culture and characterized by phagocytosis and expression of MAX 1 antigen and non-specific esterases. The macrophages remaining in suspension in the bags were activated by exposure to immunostimulating compounds used alone or in combination (recombinant human gamma-interferon and muramyldipeptide). Activated macrophages were cytotoxic in vitro against U 937 or ovary carcinoma tumor lines (95% cytotoxicity) at a 1/1 effector/tumor cell ratio. The antitumoral potency of activated macrophages was confirmed in vivo where adoptive transfer of one million human macrophages twice a week to nude mice bearing human ovary carcinoma caused a marked regression of the primary tumor.

Animals↗
PubMed1988

Integrated plasma and synovial fluid pharmacokinetics of tenoxicam in patients with rheumatoid arthritis and osteoarthritis: factors determining the synovial fluid/plasma distribution ratio.

Single oral doses of 40 mg of the nonsteroidal antiinflammatory drug, tenoxicam, were given to four patients (three with rheumatoid arthritis, one with osteoarthritis). The concentrations of the drug in synovial fluid and plasma were measured by a specific high-performance liquid chromatography method. The unbound fractions of the drug in both fluids were determined at pH 7.4 and 37 degrees C by equilibrium dialysis. The possible influence of the pH on the protein binding was also assessed. The total concentration time curves in plasma and synovial fluid were fitted to linear oral 1 and 2 compartment body models with an additional synovial fluid compartment connected to the central compartment. The unbound fractions of drug in synovial fluid and plasma were on average 0.015 and 0.011, respectively: not significantly different from each other. The protein binding of tenoxicam was pH dependent with increased free fractions at pH values less than 7.4. The average peak concentrations of tenoxicam in plasma and synovial fluid were 4.3 and 1.4 micrograms/ml, respectively. The mean ratio of the areas under the total concentration time curves in synovial fluid and plasma was 0.42, which corresponded to the steady state of equilibrium ratio of the total drug concentrations in the two body fluids. Two hypotheses were tested: hypothesis I assuming that equilibration across the synovial tissue takes place between the unbound, unionized tenoxicam molecules; hypothesis II assuming that equilibration across the synovial tissue is established between the unbound (unionized + ionized) tenoxicam molecules. Based on the available evidence hypothesis II was rejected.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1988

Excretion of tiapamil in breast milk.

The excretion of tiapamil in breast milk was studied in six lactating mothers (3-7 days post partum) following a single oral 600 mg dose of the drug. The milk/plasma ratio of tiapamil derived from the areas under the plasma and milk concentration-time curves was 0.44 +/- 0.10 mean +/- s.d.). Assuming an intake of 350 ml of milk during a dosing interval of 12 h, the newborn would be exposed at the maximum to 0.053 mg tiapamil. This small amount does not represent a risk for the baby.

Adult↗
PubMed1988

Clinical pharmacology of flumazenil.

(1) Flumazenil is a highly specific benzodiazepine (BZ) antagonist. It exerts its effect by competitive interaction at the BZ receptor site. (ii) Flumazenil antagonizes all central BZ effects irrespective of its contiguity to the BZ administration. (iii) The pharmacological effect of flumazenil depends upon the number of BZ receptors that can be occupied by flumazenil according to the mass-action law. Receptor occupancy is determined by the affinity of the BZ for the receptor and the free BZ concentration near the receptor. (iv) The minimal effective dose of flumazenil is 0.2 mg. After extreme BZ overdose 1 mg may be needed. (v) The optimal dosing strategy starts with an initial dose of flumazenil 0.2 mg i.v. The administration of further low doses of 0.1 mg at 1-min intervals allows the interruption of the injection of flumazenil exactly at the stage of vigilance that is most convenient for the patient. (vi) The duration of effect depends upon the type and dose of the administered BZ, the dose of flumazenil, and the time interval between flumazenil and the BZ administration. (vii) The therapeutic or safety index is above 3000, which means that a 3000 times overdose is still tolerated.

Animals↗
PubMed1988

Immunotherapy of cancer: experimental approach with activated macrophages proliferating in culture.

Murine macrophages isolated from the peritoneal cavity or from the lung were continuously grown and expanded in vitro on a confluent layer of "mesothelial or endothelial" feeding cells. These cell lines could be obtained from C57B16 or BalbC mice and were nontumorogenic in nude mice. The macrophages were characterized by their capacity to phagocytose yeasts and by the presence of nonspecific esterases, of Fc receptors, and of specific antigens (MAC1 ...). In vitro, these macrophages were fully activated and were tumoricidal against different tumor cell lines. In vivo, adoptive transfer of the expanded macrophages to mice bearing EMT6 sarcoma or 3LL metastasizing carcinoma inhibited the growth of the primary tumors and the development of metastases. Local injection in the vicinity of the primary tumor and i.v. transplantation were effective. The adoptive transfer of expanded macrophages could lead to a new kind of immunotherapy of neoplastic diseases combining selective amplification with effective activation of macrophages as key effector cells.

Animals↗
PubMed1987

Screening of degradative enzymes from articular cartilage in experimental osteoarthritis.

Sixteen rabbits were killed 12 weeks after sectioning of the right knee anterior cruciate ligament. The left unoperated knee served as a control. The surface area of fibrillated cartilage from femoral condyles and tibial plateau was evaluated and expressed as a percentage of articular surfaces area. Cartilage from the femoro-patellar surfaces was homogenized for the quantification of several degradative activities, based on the release of digested products. Acid phosphatase, several glycosidases and neutral protease activity from the operated joint cartilage were significantly elevated, while collagenolytic activity was unmodified. The percentage of fibrillated cartilage correlated positively with arylsulfatase, glucosidase and neutral protease but negatively with mannosidase and fucosidase. The results may be consistent with the hypothesis of a sequential degradative process leading to cartilage destruction.

Animals↗