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Biomedical subjects

J M Thomson

Publications and source records attributed to J M Thomson.

At least 73 records · Page 4Linked to original sources
PubMed1980

Heparin and partial thromboplastin time: an international survey.

The reliability of routine partial thromboplastin time (PTT) methods in the measurement of the anticoagulant effect of heparin has been assessed in a study involving over 300 hospitals in the U.S. and overseas. Commercial PTT methods were relatively insensitive to heparin, added in vitro, compared with the standardized PTT method tested by the same laboratories. Non-commercial, locally-prepared reagents compared well with the standardized method particularly in the detection of a low concentration of heparin. The value of a sensitive reference preparation for the calibration of routine PTT reagents used in heparin control is demonstrated.

Blood Coagulation↗
PubMed1980

Fibrinogen determination in a series of proficiency studies.

Fibrinogen estimations were performed in four quality control proficiency studies conducted by the National (UK) Reference Laboratory for Anticoagulant Reagents and Control for over five hundred hospitals in the UK and overseas during 1976--1978, to evaluate the various techniques in current practice. More than 30 different estimation techniques were employed by participants and these could be classified into eight groups. The success in detecting a fibrinogen level below the normal range ('sensitivity') and reliability in providing a normal result for a value within the normal range ('specificity') have been determined. No method failed in both aspects. The tyrosine, clot weight, immunological and Clauss technique appeared reasonably satisfactory. The best results were obtained with the Clauss technique although the difference between this and the other quantitative techniques did not achieve statistical significance. Some were less dependable, notably the turbidity techniques and the thrombin time. Although no technique appeared to be superior to others from the standpoint of precision, turbidity techniques appeared to be the least precise showing the largest co-efficient of variation.

Fibrinogen↗
PubMed1980

A double-blind cross-over study of piperazine oestrone sulphate and placebo with coagulation studies.

A double-blind trial of piperazine oestrone sulphate was performed over a period of 14 months on 55 menopausal women complaining of depressiona and hot flushes. Depression was not affected but the hot flushes were significantly lessened by the oestrogen treatment. After three months of piperazine oestrone sulphate there were no significant accelerations of prothrombin time or increases in factors VII or X but, after six months, there was an acceleration in the prothrombin time. After 14 months those who received piperazine oestrone sulphate for the first six months showed a significant increase in alpha 1-antitrypsin and factor VIIR:AG. Oestrone piperazine sulphate appears to produce less marked changes in coagulation than oestrogen-containing oral contraceptives or conjugated equine oestrogens.

Blood Coagulation↗
PubMed1980

The control of heparin therapy by the activated partial thromboplastin time: results of collaborative studies.

Collaborative studies to measure the effect of heparin on the activated partial thromboplastin time (APTT) have been conducted by the National (UK) Reference Laboratory for Anticoagulant Reagents and Control (NRLARC) in Great Britain and overseas and by the College of American Pathologists (CAP) in the United States. The value of multicentre trials to assess the various APTT methods, as opposed to single centre investigations, is discussed. Results from the NRLARC studies indicate that APTT methods from commercial manufacturers are relatively insensitive to heparin at low levels, compared with the standardised APTT reagent and technique produced by the NRLARC. The latter shows good sensitivity over a wide range of heparin concentrations. Variables encountered with the different commercial APTT methods are outlined. An APTT reagent should show good sensitivity at low levels and a linear response to a wide range of heparin concentrations. The in vivo response of the NRLARC standardised method in detecting circulating heparin during a clinical study of low-dose heparin prophylaxis during surgery has also been evaluated.

Blood Coagulation Tests↗
PubMed1980

Transsexualism: a legal perspective.

This paper begins with a discussion of the current legal definition of sex laid down in Corbett v Corbett. The implications of this test for three areas of the law, marriage, birth certificates and employment are then examined. Solutions from the United States of America and West Germany are studied and the suitability of similar solutions being transplanted into British law discussed.

Birth Certificates↗
PubMed1979

Effects of manufacturing oral contraceptives on blood clotting.

In monitoring the effects of industrial exposure resulting from the pharmaceutical manufacture of oestrogen-progestogen combinations by coagulation studies acceleration of some clotting tests was found. The most pronounced changes were in workers most closely associated with the industrial process. Less pronounced changes were found in women employees not closely concerned with the processing and may have been secondary to the postmenopausal bleeding to which they were prone. A safer work procedure elaborated by the Employment Medical Advisory Service was monitored by clotting studies for over a year but the three most highly exposed subjects showed no substantial improvement.

Blood Coagulation Disorders↗
PubMed1979

Quality control trials of prothrombin time: an assessment of the performance in serial studies.

A series of collaborative exercises on the one-stage prothrombin time test involving hospitals in Britain and overseas was performed between 1972 and 1977. The British Comparative Thromboplastin (BCT) and the lyophilised test plasmas were issued from the National (UK) Reference Laboratory for Anticoagulant Reagents and Control. Participants were asked to test the plasma samples with the BCT using the recommended technique. Variability of performance was assessed by the 'index of reliability' based on the plasma variance and error variance within each exercise. The results show that hospitals have attained higher precision in the later trials.

Humans↗
PubMed1979

Changes in the coagulation of blood during resection of the abdominal aorta.

In 33 patients, a significant fall in the fibrinogen level occurred during an operation to replace the abdominal aorta by a bifurcated prosthesis. There was a similar, but less marked, fall in the fibrinogen level of ten patients having a femoropopliteal vein bypass. A concomitant drop in the plasma plasminogen value was also found. Results of specific laboratory tests for intravascular clotting and activation of fibrinolysis were negative. This suggests that fibrinogen may be removed by physical means. The fall in fibrinogen was so low in some patients that the routine administration of a conventional dosage of heparin could be dangerous.

Adult↗
PubMed1978

Treatment policies affecting survival in patients with carcinoma of the cervix.

Radiotherapy treatment techniques were evaluated according to survival rates among more than 800 patients with Stage I and II carcinoma of the cervix. An increased survival rate was noted when a Fletcher tandem and ovoids and the Fletcher technique of external irradiation and fractionated radium therapy were applied. This increase was due to a larger radiation dose to the anoxic tumor core and to external irradiation shrinking the tumor to within the high-dose range of radium therapy.

Female↗
PubMed1978

The use of pelvic arteriography in assessing carcinoma of the cervix.

Twenty-nine patients underwent pelvic arteriography as a part of their pre-radical-hysterectomy evaluation for cervical carcinoma. False-positive studies were as common as false-negative studies, not only in the assessment of tumor extension locally, but also in determining the presence of pelvic lymph node involvement. Twenty-one patients underwent preoperative irradiation, but the lack of correlation was similar in 8 patients who were treated by primary radical surgery a few days after arteriography. The clinical estimate of tumor extension corresponded more closely to the pathologic findings than pelvic arteriography.

Angiography↗
PubMed1977

Stability studies on lyophilised reference thromboplastins for standardisation of prothrombin-times.

An international framework for anticoagulant control has been developed based on British Comparative Thomboplastin (B.C.T.) and the model provided by the British system for anticoagulant control. An alternative international system has been proposed, based on lymphilised thromboplastins prepared at the National Institute of Biological Standards and Control, London. Since 1969, stability studies on two of the N.I.B.S.& C. reagents, the primary material 67/40 and the secondary thromboplastin 69/223, have been in progress at the National (U.K.) Reference Laboratory for Anticoagulant Reagents and Control, Manchester. Both the proposed N.I.B.S.&C. reference preparations have deteriorated, while two lyophilised reagents prepared at the National (U.K.) Reference Laboratory have revealed no evidence of instability. In national and international standardisation reliance on B.C.T. should continue.

Anticoagulants↗
PubMed1977

Conjugated equine oestrogens and blood clotting: a follow-up report.

A follow-up study of blood clotting and platelet aggregation was performed on 21 women who had received long-term hormone replacement treatment with conjugated equine oestrogens. The prothrombin time and factor VII and X values were significantly accelerated after three months, but there was no further increase with continual administration for 18 months. After 12 to 18 months' treatment, however, thrombin-induced platelet aggregation (Chandler's tube) was also significantly accelerated, which suggested a widening spectrum of effect. No overall acceleration of "intrinsic" clotting (partial thromboplastin time and thromboelastography) was found during the study, but the relatively small numbers may have been responsible. Further efforts are therefore required to find formulations and doses of oestrogens which, while relieving menopausal symptoms, cause less acceleration of blood clotting and platelet aggregation.

Blood Coagulation↗
PubMed1977

Association of abnormal fibrin polymerisation with severe liver disease.

The frequent occurrence of abnormal fibrin polymerisation in patients with liver disease has recently been reported. To investigate this further, fibrin polymerisation was studied in 68 patients with cirrhosis or chronic active liver disease. Thirty-three of these patients demonstrated impairment of this phase of blood coagulation. When other tests of liver function were compared in patients demonstrating this abnormality and those in whom fibrin polymerisation was normal, it was found that the former group demonstrated significantly reduced albumin concentrations (p less than 0.0002), raised bilirubin and aspartate aminotransferase levels (p less than 0.0006 and less than 0.003 respectively), and greater prolongation of the one-stage prothrombin time (p less than 0.001) with more marked reduction in factor VII levels (p less than 0.002) compared with the latter patients. It is concluded that defective fibrin polymerisation occurring in patients with liver disease indicates the presence of severely impaired hepatocellular function. This might account for the grave prognosis reported in cirrhotic patients with abnormal fibrin polymerisation who also suffer bleeding from gastro-oesophageal varices.

Aspartate Aminotransferases↗
PubMed1977

Factors affecting survival in over 500 patients with stage II carcinoma of the cervix.

Charts were reviewed of 519 patients with stage II (League of Nations) carcinoma of the cervix to determine those factors in the history, work-up, and treatment which affected survival. Those factors which correlated with a significant decrease in five-year survival were abnormal admission blood urea nitrogen level or excretory urogram, a history of pelvic pain or weight loss over 10 kg (20 lbs.), or tumor extension to the endocervix or uterus. These factors, as well as the results of lymphangiography, should be included in the staging of carcinoma of the cervix.

Adenocarcinoma↗