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Biomedical subjects

T Forster

Publications and source records attributed to T Forster.

67 records · Page 4Linked to original sources
PubMed1983

An assessment of the sensitivity of 3 bleeding time techniques.

The sensitivity of 3 bleeding time techniques to an aspirin-induced defect of platelet function has been assessed in 35 normal volunteers. A carefully standardised Ivy technique was compared with 2 commercial devices for a template bleeding time, the Simplate II and the Thrombolette. The standardised Ivy and the Simplate II were found to have a similar sensitivity; the Thrombolette tended to be less sensitive but the difference was not significant.

Aspirin↗
PubMed1980

A sex difference in the bleeding time.

The bleeding time by a modified Ivy technique was estimated on 128 normal volunteers, 59 men and 69 women. The bleeding time was found to be significantly longer in women than men (p < .001). This was not attributable to a difference in platelet count nor to any detectable difference in platelet aggregability. It is likely that a difference in blood vessels or supporting tissues is responsible for the observed difference.

Adolescent↗
PubMed1980

Heparin and the activated partial thromboplastin time--a difference between the in-vitro and in-vivo effects and implications for the therapeutic range.

The in-vivo sensitivity to heparin of activated partial thromboplastin time (aPTT) reagents is different from the in-vitro sensitivity. Equivalent therapeutic ranges for reagents of very different sensitivities may be determined from the regression line of aPTT against whole blood clotting time. The commonly used ratio of 1.5 to 2.5 times the normal control value is appropriate for some reagents, but for the other reagents a higher or lower range is appropriate. A suitable aPTT reagent for heparin control should be sensitive both to a threshold effect of heparin and to increasing dosage. Some reagents discriminate poorly at the threshold level.

Heparin↗
PubMed1980

Effects of ACTH on the synthesis and metabolism of prostaglandin in rat kidney.

Prostaglandin (PG) synthetase activity of rat kidney medulla microsomal fraction was determined in vitro using I-14C-arachidonic acid as substrate. Natural ACTH resulted in a dose dependent suppression of PGE2 formation in vitro. The biosynthesis of PGE2 alpha was enhanced in the presence of ACTH (cortrophin). ACTH4--10 (1-Phe7 or d-Phe7) resulted in decreased PGE2 synthesis. The ratio of PGF2 alpha/PGE2 increased in proportion to the concentration of natural ACTH. The increase in the ratio of PG-s was more pronounced when ACTH4--10 fragments were applied. Natural ACTH in a dose dependent manner inhibited the prostaglandin dehydrogenase activity of kidney cytosol fraction in vitro. Prostaglandin inactivation was suppressed only by high doses of ACTH4--10 (d-Phe7). The data indicate that the natural ACTH and ACTH4--10 fragments might have a physiological role in the regulation of the prostaglandin system of a non-steroidogenic tissue.

Adrenocorticotropic Hormone↗
PubMed1980

Effect of ACTH on prostaglandin induced vascular permeability.

Increased vascular permeability was induced by prostaglandin E2 (PGE1), arachidonic acid and compound 48/80 in male rats. Natural ACTH in a dose-dependent manner inhibited Evans blue exudation elicited by arachidonic acid or compound 48/80, however, it was ineffective against PGE1. ACTH4--10 (d-Phe7 and 1-Phe7) injected together with the prophlogistic agents depressed the arachidonic acid and compound 48/80 induced vascular reaction. Indomethacin pretreatment inhibited the effect of arachidonic acid on vascular permeability suggesting that arachidonic acid evoked its vascular activity by means of affecting the endogenous synthesis of prostaglandins and, on the other hand, the prostaglandin system played a role in the vascular permeability inducing effect of compound 48/80. ACTH4--10 peptide fragments free of steroidogenic action and natural ACTH inhibited locally the in vivo formation of PGS from arachidonic acid in the rat skin, resulting in a nonspecific decrease of local inflammation.

Adrenocorticotropic Hormone↗
PubMed1979

The effect of adrenal and gonadal hormones on vascular permeability in rat skin.

The effect of adrenal and gonadal hormones on vascular permeability induced by intradermal injection of prostaglandins (PGs) E1, F2alfa, arachidonic acid and compound 48/80 have been examined in the rate. PGE1, arachidonic acid and compound 48/80 produced an increase in local vascular permeability. PGF2alfa decreased the action of these vasoactive agents, when it was injected in a mixture intradermally with PGE1, arachidonic acid and compound 48/80. Vasoactive response induced by PGE1, arachidonic acid and compound 48/80 was inhibited by the removal of adrenals and testes, and it was restored to normal by injection either of cortisol, deoxycorticosterone (DOC) or testosterone. In adrenalectomized rats, no change was observed in the inhibition of vascular permeability elicited by PGF2alfa response to compound 48/80. The blocking effect of PGF2alfa on vascular permeability evoked by PGE1 and arachidonic acid showed a considerable decrease. After orchidectomy the inhibitory effect of PGF2alfa on the vascular permeability induced by arachidonic acid and compound 48/80 was completely blocked, while in the case of PGE1 the inhibition was partial. Testosterone treatment restored the anti-inflammatory effect of PGF2alfa against compound 48/80. Ovariectomy was without any effect on vascular response.

Animals↗
PubMed1978

Control of oral anticoagulants by the prothrombin time: a plea for uniformity.

Six trromboplastins commonly used for prothrombin time determinations were studied. Prothrombin times of patients who were receiving oral anticoagulant therapy varied widely, depending on the origin of the thromboplastins. The therapeutic range which is recommended with one thromboplastin is often quite different from that recommended with another, and as a result, the therapeutic ranges of different institutions may show no overlap. Management of patients and comparison of therapeutic results would be facilitated if all thromboplastins in use in Australia were standardized by comparison with the Australian Reference Thromboplastin.

Administration, Oral↗
PubMed1976

High dose methotrexate therapy of solid tumors: observations relating to clinical toxicity.

In clinical studies performed during 111 infusions of high dose methotrexate (MTX) we have evolved a clinical and laboratory protocol which permits such therapy without prohibitive risk to the patient. The plasma MTX data obtained indicate that pharmacokinetic disposition is dose related during these infusions and that such data are useful in identifying patients at risk from serious toxicity.

Adolescent↗
PubMedDate not supplied

Alcohol-induced congestive cardiomyopathy in adult turkeys: effects on myocardial antioxidant defence systems.

The effects of chronic intake of dietary alcohol upon left ventricular function, activities of myocardial antioxidant enzymes, reduced glutathione (GSH) content and lipoperoxidation (measured as the formation of diene conjugates and lipid-soluble fluorescence) were studied in adult domestic Nicholas turkeys. The non-invasive evaluation of left ventricular function by echocardiography revealed an impaired contractile function (the calculated fractional shortening values were 31.1 +/- 4.1% in the alcoholic group and 38.8 +/- 4.4% in the controls) and dilatation of the heart in the alcoholic birds. The changes in the non-invasive parameters of the left ventricle indicate that the adult Nicholas turkey developed congestive cardiomyopathy secondary to the ingestion of ethanol. In the hearts of normal adult turkeys, high GSH content (2.39 +/- 0.25 mumol/g wet weight) and superoxide dismutase activity were found, as compared to other animals, indicating the relatively higher development of antioxidant defence systems. Compared to the controls, significant increases were noted for all the antioxidant enzymes investigated (superoxide dismutase, catalase and glutathione peroxidase) and a moderately significant decrease in the GSH content was found in the left ventricle of alcoholic birds. The changes in GSH concentration and antioxidant enzyme activities might indirectly indicate some involvement of free radicals in the pathogenesis of ethanol-induced myocardial lesion. However, the levels of in vivo lipoperoxidation in the alcoholic birds did not significantly vary from those of control turkeys. Based on these findings, it appears that the reactive oxygen radicals may play a less important role in the pathogenesis of alcohol-induced cardiomyopathy in turkeys--probably due to the higher development of myocardial antioxidant defence systems.

Alcoholism↗
PubMedDate not supplied

[Staging and therapeutic options in local prostatic carcinoma].

Since the introduction of prostate specific antigen (PSA) into widespread use in clinical practice for early detection of prostate cancer (PCa), in combination with digital rectal examination (DRE), there has been a marked increase in the incidence of localized, potentially curable, disease coupled with a simultaneous decline in regional and metastatic prostate cancer in the least years. After the diagnosis of adenocarcinoma of the prostate has been histologically confirmed, an accurate assessment of the stage--or extent--of the disease should be made. We will provide a critical assessment of the currently employed PCa staging modalities. Therapeutic options in locally defined PCa are analyzed. Intracapsular PCa (T1a-T2b N0 M0) is preferably managed by radical prostatectomy, "insignificant" cancers may be treated by watchful waiting. The outcome of irradiation is not as predictable as radical surgery. Neoadjuvant treatment with radical prostatectomy in locally advanced PCa is probably not as efficient as believed; in some instances the value of adjuvant treatment is undecided. As it seems irradiation in conjunction with androgen deprivation can equal efficacy of surgery.

Humans↗
PubMedDate not supplied

Can we assess the changes of ventricular filling resulting from acute allograft rejection with Doppler echocardiography?

We investigated the value of several Doppler echocardiographic measurements for the diagnosis of acute allograft rejection after orthotopic heart transplantation. In all, 144 transmitral flow velocity curves and 159 internal jugular venous flow velocity curves were recorded by continuous wave Doppler echocardiography, and the results were compared with the histologic findings. The recordings were evaluated with a computer-aided analysis system. The Doppler measurements did not show any significant correlation with the biopsy results. Only one recording obtained during a moderate acute rejection episode supported the hypothesis about the relation between jugular venous flow and cardiac rejection. We conclude that these Doppler echocardiographic measurements are not suitable to detect acute allograft rejection noninvasively.

Adult↗