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Biomedical subjects

G Mayer

Publications and source records attributed to G Mayer.

At least 253 records · Page 14Linked to original sources
PubMed1985

Prediction of toxicity using quantitative structure-activity relationships.

The relationships between toxicity and physicochemical indices of derivates of four chemical groups: of phenol, benzene, aniline and aliphatic amine were studied. Using the Hansch model the feasibility of using the octanol/water partition coefficient, electronic and steric constants was estimated. The acute lethal doses and no effect levels for rats were found not to be predictable using these parameters. The molecular connectivity indices, which describe the topology of the molecular structure have shown a closer relationship to toxicity, than the physicochemical parameters. The application of both physicochemical and molecular connectivity indices provided the best correlations and has been recommended for prediction of toxicological parameters.

Amines↗
PubMed1985

Intravenous streptokinase in acute myocardial infarction.

Intravenous (IV) fibrinolytic therapy, a recent area of research, has a great deal of applicability in emergency medicine. We report our experience with 30 patients treated with this method. Thirty consecutive patients in the early stages of acute evolving myocardial infarction (AMI) were assigned to receive high-dose IV streptokinase, 1.5 million units over a 30-minute period. Patients presented to the treating hospital at a mean time of 1.21 +/- 1.08 hours, and treatment commenced at a mean time of 2.77 +/- 1.31 hours after the onset of symptoms. Using standard clinical criteria, 86.7% (n = 26) of the patients reperfused initially. Two, however, reoccluded within the first 48 hours, and their clinical symptoms of myocardial infarction reappeared. By clinical observation 80% (n = 24) of the patients reperfused, and myocardial salvage was observed. Twenty-four patients with clinical reperfusion and one additional patient had patency of the affected artery, yielding a reperfusion rate of 83.3% (n = 25) as judged by angiography within one week of AMI. Both patients who had reoccluded clinically also were found to be occluded on angiography. Clinical and angiographic methods yield very similar results for the judgment of reperfusion (80% vs 83%, respectively, with no significant difference, P not significant). The results of our study tend to confirm the efficacy of IV streptokinase as a valuable management tool for early myocardial infarction.

Aged↗
PubMed1985

Hip replacement in acetabular protrusion.

The medial defect in acetabular protrusion makes it necessary to construct a strong implant bed for the cup prosthesis. Autogenous spongiosaplasty of the floor of the acetabulum combined with wire reinforcement of the cemented plastic cup has given good results in 28 patients followed for 3 (1-6) years.

Acetabulum↗
PubMed1985

[Preliminary study in female rats of the immunoregulatory effect of estradiol, progesterone and pituitary prolactin on natural killer-like cell mediated cytotoxic activity].

A spontaneous non-immune natural killing-like cytotoxic activity is induced in cyclic non mated virgin F/344 females by progesterone + oestradiol or progesterone alone treatment after bilateral ovariectomy. Many indications attribute this cytotoxic response to the absence of the mating stimulated pituitary prolactin release which normally rescues the corpora lutea from regression, and brings about the necessary progesterone for pregnancy or pseudopregnancy.

Animals↗
PubMed1985

[Prolonged survival of skin allografts in rats by injection of serum or a serum fraction extracted from pregnant rats].

This work report the partial purification of an alpha 2-macroglobulin present in the serum of allopregnant rats. Ultrogel filtration followed by immune absorption on different antisera were used giving a single band on polyacrylamide gel electrophoresis. This fraction was able to inhibit in vitro T cell cytotoxic response to allogenic cells. When administered repeatedly to rats it significantly increased the survival of skin allograft. This alpha 2-macroglobulin fraction isolated from allopregnant rats was denominated IRG to its graft rejection inhibitory activity.

Animals↗
PubMed1985

[Femur shaft fractures in artificial hip joint replacement].

In a total of 1980 patients who underwent total hip replacement 0.8% suffered from intra- and postoperative fractures of the femoral shaft. These spontaneous fractures were preconditioned by damage of the cortical layer due to rheumatoid arthritis, aseptic and septic looseening of the prosthesis as well as local trauma. In most cases stability could be restored by plate osteosynthesis, sometimes in combination with change of the prosthesis.

Aged↗
PubMed1985

[Apical hypertrophic myocardiopathy. Apropos of 10 cases].

Apical hypertrophic cardiomyopathy is a recently defined subgroup of primary hypertrophic cardiomyopathy. Ten new cases are studied. The electrical features (anomalies of repolarisation) were constant and giant negative T waves were observed in 3 out of 10 cases. Two-dimensional ultrasonography confirmed the diagnosis in every case; the optimal views consisted of 4 cavity scans obtained by the apical approach. When angiography was performed (7 cases out of 10), it confirmed the ultrasonographic findings and was able to eliminate any coronary artery lesions. The patients had a mean age of 48.3 years with a marked male predominance (sex ratio of 0.8) and all of the patients are alive with a mean follow-up of 3.4 years. The functional handicap was moderate (class III: 1 case, class II: 5 cases and class I: 4 cases) and did not progress during the period of follow-up. The family surveys performed revealed that apical hypertrophy can be integrated into the spectrum of segmental hypertrophic cardiomyopathy. In two cases, this survey revealed the coexistence in the same family of segmental hypertrophy with different topography. The long term prognosis of this disease is unknown and the authors consider that the risk of ventricular arrhythmia justifies routine rhythmological evaluation in order to guide subsequent treatment.

Adult↗
PubMed1984

Artificial replacement of the hip joint in severe coxarthroses secondary to acetabular dysplasia.

The reconstruction of hip joints is problematic in cases of subluxation coxarthrosis, since the dysplastic acetabulum's lack of depth does not primarily allow reliable anchorage of an acetabular prosthesis component. Since enlargement of the acetabulum by fraising is ruled out on biomechanical grounds, a suitable bed for the implant can only be created by reconstructing the roof of the acetabulum. Laterally supported osteoplasty has proved to be a suitable method for repairing dysplastic acetabular defects, involving screwing of autogenic or allogenic grafts firmly onto the acetabular margin. The radiological and clinical results of 70 hips followed up confirm the efficiency of the endoprosthetic acetabulum implanted by this method in cases of marked dysplastic coxarthrosis.

Acetabulum↗
PubMed1984

Myocardial infarction management with peripheral streptokinase.

The early management of myocardial infarction (MI) is undergoing a new evolution. Aggressive treatment and new invasive modalities have brought improved prognosis to these patients. Intracoronary administration of fibrinolytic agents is rapidly gaining wide acceptance. We report a pilot protocol for administration of peripheral intravenous (IV) versus direct intracoronary fibrinolytic agents in acute MI. Thirty patients with acute evolving MI were assigned consecutively to receive fibrinolytic therapy; 15 patients received intracoronary streptokinase and 15 received peripheral IV streptokinase at a dosage of 1.5 million units over a 30-minute period. Evaluation by clinical symptoms, ECG changes, and hemodynamic studies by angiography and radionuclide ventriculography indicated comparable and beneficial results for both groups. Patients assigned to the IV therapy were able to receive streptokinase therapy 1.5 hours earlier than those receiving intracoronary therapy, and they had a higher incidence of reperfusion. We conclude that IV streptokinase therapy may be preferable to intracoronary therapy in view of a higher reperfusion frequency, fewer complications, and greater ease of administration. With both treatment modalities, comparable improvement in left ventricular function was noted. Institutions that do not have invasive techniques available may well be the first to benefit from this method of myocardial salvage, and we encourage cooperation between emergency and cardiology departments.

Adult↗
PubMed1984

Rat pregnancy induces two suppressor cell activities.

Pregnancy in rat is able to stimulate two suppressor cell activities. One is specific to the paternal histocompatibility antigens and it resides in the T-lymphocyte population. The second is nonspecific and is of non-T nature. The use of various methods for pseudopregnancy and deciduoma installation has allowed the demonstration of two inducing circuits: (a) the presence of fertilized ova in the female genital tract and (b) the progestation hormonal status.

Animals↗
PubMed1984

Rat pregnancy immunoregulatory circuits are progestation hormonal status, decidual tissue, embryo-trophoblast and late pregnancy changes dependent.

We have tested the spleen cells of rats for their reactivity to mating and unrelated (third party) strain alloantigens during pregnancy, pseudopregnancy, and traumatic deciduoma installation. By cytotoxic T-lymphocyte assays, after 7-day one-way mixed lymphocyte cultures (MLC), we detected the presence of many immunoregulatory circuits among rat pregnancy and postpartum. They are progestation hormonal status, decidual tissue, embryo-trophoblast, late-pregnancy-parturition-associated changes, and lactation-hormonal-status dependent.

Animals↗
PubMed1984

[Treatment of chondral and osteochondral fractures of the knee joint].

This paper deals with the different surgical procedures which may be performed for reconstructing destroyed structures of the cartilage or for palliating pain in delayed cases. Persisting defects of the cartilaginous surface will lead to osteoarthrotic degeneration of the joint. Therefore, the authors emphasize the immediate surgical revision of the injured knee joint. The results obtained in this way are good, especially in younger patients.

Adolescent↗