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Biomedical subjects

S Roman

Publications and source records attributed to S Roman.

At least 91 records · Page 5Linked to original sources
PubMed1984

Inhibition of salicylate binding to normal plasma by extracts of uremic fluids.

We previously reported that an extract of uremic plasma reduces binding of phenytoin and tryptophan by normal plasma and plasma albumin. This effect appears to reproduce the impaired binding of many drugs and several endogenous metabolites by uremic plasma. In the present study we further characterized the properties of extracts from uremic sera and body fluids using binding of salicylate as a model. Salicylate was chosen because it binds to both of the main albumin binding loci for aromatic, acidic drugs. Using a computer-assisted, least-squares, curve-fitting program, LIGAND, we found that the most satisfactory model for salicylate binding to 1:10 diluted normal plasma was a binding number (n) of 2 mol of salicylate per mole of albumin with an association constant (k) of 2.85 X 10(4) L/mol, an additional binding of 0.5 mol to other sites on albumin or to other proteins, and nonspecific binding of 21%. Addition of uremic pleural fluid extract to diluted normal plasma produced a monotonic decline in k to 0.17 X 10(4) L/mol with no change in n except possibly at the highest dose of uremic inhibitor. This pattern of competitive inhibition indicates presence of unknown ligands in the uremic extract that compete at both binding loci. More efficient extraction methods might also yield additional ligand(s) that inhibit through a noncompetitive mechanism.

Adult↗
PubMed1984

[Accentuation of myocardial ischemia during coronary recanalization in the acute phase of myocardial infarction].

Coronary recanalisation during the acute phase of myocardial infarction, especially by in situ infusion of thrombolytic agents, is accompanied in most cases by rapid regression of chest pain and a reduction in the degree of ST elevation. However, a multicentre retrospective study of 104 attempts at recanalisation, including 78 successful procedures, showed in 10 cases (12.8 p. 100), an apparently paradoxical accentuation of the chest pain with or without increased ST elevation, at the time of angiographically demonstrable recanalisation. This phenomenon may be interpreted as being the result of aggravation of the ischaemia of the border zone, the objective of therapy. Several pathogenic hypotheses, all with experimental proof, may be suggested to explain these observations (haemorrhagic infarction, non reperfusion, ischaemic contraction due to massive intracellular flow of calcium, etc.). It is usually associated with arrhythmias and may be considered to be a reliable sign of recanalisation. It may also explain certain cases of persistence of chest pain and ECG changes despite the demonstration of a permeable epicardial artery on initial coronary angiography.

Coronary Angiography↗
PubMed1983

Comparative behaviour of the components of the factor VIII complex in acute myocardial infarction.

The three components of the factor VIII complex: VIII coagulant (VIII:C), VIII related antigen (VIII R:Ag) and the VIII related von Willebrand factor (VIII R:WF) were studied in patients with acute myocardial infarction (AMI). Using a carefully standardized technique for the determination of VIII R:WF, a significantly higher R:WF level was found in 32 patients compared to 19 control subjects, confirming our previous results. However VIII R:AG was increased to an even greater extent, resulting in a VIII R:Ag/VIII R:WF ratio of 1.58 +/- 0.084 in patients, compared to 1.21 +/- 0.045 in controls. A similar increase of the VIII R:AG/VIII:C ratio was noted in the 13 patients in whom VIII:C was investigated. In 7 patients with severe AMI who could be investigated twice the plasma levels of both VIII R:Ag and VIII R:WF were found to be lower a week after the acute event than during the first 48 hours. However the VIII R:Ag/VIII R:WF ratio was not significantly reduced after 7 days. Acute phase reaction and endothelial injury resulting in release of multimers which are less polymerised are probably involved in the above changes.

Adult↗
PubMed1981

Increased plasma antithrombin III level in hyperlipidemic subjects.

When compared to values obtained in healthy normolipidemic normal weight control subjects, the plasma antithrombin III level determined by immunological, clotting and thrombin-agarose diffusion techniques was found to be obviously decreased in patients with decompensated cirrhosis of the liver and slightly but significantly increased in hyperlipidemic and especially in hypertriglyceridemic subjects. Plasma antithrombin III was positively correlated with serum cholesterol level, the logarithm of serum triglyceride concentration and serum pseudocholinesterase activity. A weaker correlation between plasma fibrinogen and antithrombin III was noted in the investigated clinical material. It is suggested that the accelerated fatty acid and lipoprotein turnover occurring in many subjects with type IIb and type IV hyperlipoproteinemia might be accompanied by an enhanced hepatic protein synthesis involving various liver secretion enzymes and clotting factors as well as antithrombin III.

Adult↗
PubMed1980

Increased ristocetin-cofactor in acute myocardial infarction: a component of the acute phase reaction.

When compared to the values obtained in healthy normal-weight, normolipemic controls, the plasma level of ristocetin-cofactor (VIII:R-cof.) was found to be much higher in patients with acute myocardial infarction and in postoperative conditions (4--5 days after a major surgical intervention). A lesser increase of VIII:R-cof. was noted in atherosclerotic patients without acute occlusive accidents and no significant changes of this plasma factor could be observed in hyperlipemic subjects without obvious clinical atherosclerosis. Serial studies emphasized a tendency towards normalization of plasma VIII:R-cof. as the acute phenomena of a myocardial infarction subsided. The above mentioned data suggest that the high levels of VIII:R-cof. recorded in myocardial infarction are mainly caused by a systemic acute phase reaction and to a lesser extent by endothelial damage. Delayed clearance of VIII:R-cof. subsequent to a hepatic dysfunction or to a modified pattern of protein metabolism during the above mentioned acute phase reaction might also contribute to the high level of this plasma factor.

Adolescent↗
PubMedDate not supplied

Proton magnetic resonance and human thyroid neoplasia. II: Potential avoidance of surgery for benign follicular neoplasms.

Thyroid cancer is rare, but many thyroidectomies continue to be performed simply to exclude a diagnosis of malignancy. The purpose of this study was to determine the potential financial savings associated with the use of proton magnetic resonance analysis of follicular neoplasms. Proton magnetic resonance spectroscopy was performed on tissue obtained at the time of surgery from 98 consecutive solitary or dominant thyroid nodules. Fine-needle biopsies were also performed on operative specimens, and the tissues assessed by proton magnetic resonance; these spectra were then compared with those obtained from tissue specimens. An estimate of potential savings was obtained by comparing the magnetic resonance data with the indications for surgery and pathology on all patients having thyroidectomy over a 10-year period. Proton magnetic resonance spectroscopy was able to distinguish between normal thyroid tissue and invasive thyroid cancer with 100% specificity. Benign follicular adenomas fall into two groups: 44% having a spectral pattern comparable with normal thyroid, and the remaining 56% demonstrating an altered spectral pattern more comparable to the malignant magnetic resonance profile. Proton magnetic resonance spectroscopy on fine-needle biopsy specimens produced spectra similar to those from tissues from the same patient. From a fine-needle biopsy specimen, proton magnetic resonance spectroscopy can identify a group of benign follicular adenomas with spectral profiles akin to those of normal thyroid cells, thus avoiding the need for unnecessary surgical excision. The potential savings in one surgical unit alone were over $1 million in 10 years.

Adenocarcinoma, Follicular↗
PubMedDate not supplied

Ultrastructural features in an erythrophagocytic T4 lymphoma.

Electron microscopic investigation allowed the identification and characterization of the atypical malignant cells in a case of T-cell lymphoma. The proliferating cells were endowed with characteristics belonging to two different lineages: phagocytic ability, complement receptors and ultrastructural features proper to the macrophagic lineage, and T-cell determinants (E receptors, T3, T4 and T11 antigens). The cells were peroxidase and esterase negative. The erythrocytes were partially or completely dehemoglobinized and presented the phenomenon of autolysis in different stages of evolution. Because this lymphoma is difficult to diagnose and is apparently resistant to therapy, its recognition and further study are warranted.

Biomarkers, Tumor↗
PubMedDate not supplied

Hemostatic variables in nephrotic patients.

The paper reviews data in the literature as well as the authors' own investigations, performed during the last seven years, concerning the hemostatic balance in nephrotic patients. The obviously increased plasma levels of fibrinogen, fibronectin, fibrin-stabilizing factor XIII, clotting factors V and VIII, von Willebrand factor as well as the enhanced platelet aggregability of such patients, associated with a decreased plasma antithrombin III, are compatible with a thrombotic tendency. On the other hand the increased plasma protein C may provide a compensative antithrombotic mechanism. A rather complex behaviour of the fibrinolytic system was noted in the nephrotic syndrome. Actually the enhanced release of tissue plasminogen activator (t-PA) from the endothelia of nephrotic patients is accompanied by an accelerated lysis of dilute blood clots, although the inhibitors of fibrinolysis such as alpha 2-macroglobulin and alpha 2-antiplasmin are increased. Failure or exhaustion of the compensative antithrombotic mechanisms would accentuate the hemostatic imbalance and favour the occurrence of thrombotic events. It is considered that increased urinary loss of antithrombin III and the enhanced hepatic synthesis of clotting factors would represent the main mechanisms involved in the production of this precarious hemostatic balance of nephrotic patients.

Antithrombin III↗
PubMedDate not supplied

Clinical studies on alpha 2 plasmin inhibitor.

Plasma levels of alpha 2 plasmin inhibitor (alpha 2 PI) were measured by both an immunological and a functional assay, and a good correlation (r = 0.793; p less than 0.001) was found between the two methods. When compared to values recorded in 17 control subjects (69.55 micrograms/ml +/- 2.04) alpha 2 PI antigen levels were found to be obviously decreased in the 10 patients with decompensated cirrhosis of the liver (41.06 micrograms/ml +/- 4.66) and slightly increased in the 13 nephrotic patients (79.73 micrograms/ml +/- 2.35) and in the 23 hypertriglyceridemic and obese patients (78.59 micrograms/ml +/- 2.23). In spite of similar plasma levels of alpha 2 PI, dilute blood clot lysis was rather accelerated in patients with the nephrotic syndrome (240 min +/- 12) and obviously delayed in patients with endogenous hypertriglyceridemia (739 min +/- 131). Apparently the rate of clot lysis is mainly determined at an earlier stage of the fibrinolytic process, represented by the balance between tissue plasminogen activator and its inhibitor. Severe decrease of alpha 2 PI may nevertheless contribute to accelerated clot lysis as noted in a patient with familial heterozygous alpha 2 PI deficiency. On the other hand increased level of factor XIII and alpha 2 PI associated to an impaired plasminogen activation would render the fibrin network more resistant to fibrinolysis.

Acute-Phase Reaction↗
PubMedDate not supplied

[A voluminous gastric lipoma simulating mediogastric stenosis].

The paper reports on a case of gastric lipoma (12/10/6 cm) placed mediocorporeally and with clinical manifestations of upper digestive obstruction, clinically and radiologically interpreted as a secondary mediogastric stenosis of an ulcer of the small curvature. The diagnosis of gastric lipoma was established intraoperatively, and by surgery the tumour was excised together with its implantation basis. The anatomopathological, clinical and therapeutical aspects of gastric lipomas are discussed.

Aged↗