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Biomedical subjects

R N Palmer

Publications and source records attributed to R N Palmer.

12 recordsLinked to original sources

United Kingdom 'Crown' indemnity for medical negligence--an overview of the first 18 months of the new scheme.

This article describes the background to the introduction of 'Crown' indemnity and summarizes the operation of the scheme. It also makes clear the limited nature of the scheme and how it does not apply, for example, to independent contractors such as general medical and dental practitioners. Also described is the nature and operation of United Kingdom medical defence organizations such as the Medical Protection Society and the services which they continue to provide to medical and dental practitioners worldwide. Early indications suggest that the new government scheme is placing a very heavy financial burden on health authorities which already suffer from underfunding and tight budgetary control.

Humans

Inhibition of cold-promoted activation of the prothrombin time studies of new siliconized borosilicate collection tubes in normals and patients receiving warfarin.

Studies of the prothrombin time in normals and patients receiving oral anticoagulant therapy revealed a partial inhibition of the in vitro cold-promoted activation of Factor VII and shortening of the prothrombin time when blood was collected in a new commercial siliconized borosilicate tube (Becton-Dickinson, Rutherford, NJ, 6418 and 6419). The data collected with normal blood indicated that the cold-promoted activation was almost totally inhibited, while the patients had only a mean reduction of 50% of the cold-promoted activation. In pregnant patients there was no inhibition of the cold-promoted activation of the prothrombin time or Factor VII using the new siliconized tubes.

Blood Specimen Collection

Circulating heparan sulfate anticoagulant in a patient with a fatal bleeding disorder.

We have identified a circulating, heparin-like anticoagulant in a patient with multiple myeloma (IgG4 lambda) who had serious clinically evident bleeding that contributed to his death. Purification of the patient's circulating coagulation inhibitor was accomplished by ammonium sulfate concentration, anion exchange chromatography, and affinity chromatography on protamine sulfate. Analysis of the purified inhibitor showed that it was a proteoglycan that comigrated with heparan sulfate on lithium acetate-agarose-gel electrophoresis and that it contained 39 per cent L-iduronic acid. Control samples of heparan sulfate and heparin contained 29 and 68 per cent L-iduronic acid, respectively. Functional coagulation studies revealed that the purified inhibitor had cofactor activity with antithrombin III that could be abolished by prior incubation with protamine sulfate or platelet factor 4. Recognition of the existence of this or of other similar inhibitors in bleeding patients is important because of the potential for treatment with agents such as protamine sulfate and platelet factor 4, which neutralize the anticoagulant effects of proteoglycans.

Blood Coagulation

Inhibition of the cold activation of Factor VII and the prothrombin time.

Normal whole blood, collected and stored in borosilicate or commercial siliconized borosilicate tubes at 4 degrees C, undergoes a time-dependent activation of Factor VII and a shortening of the prothrombin time (PT). Addition of inhibitors to Factor XII fragments (corn Hageman factor inhibitor, CHFI) or to activated Factor XII (Cytochrome-C) inhibited in a concentration-dependent way the cold-promoted activation of Factor VII and the shortening of the PT. When celite was added to whole blood in polypropylene tubes at 4 degrees C, Factor VII was activated and the PT shortened. Preincubation of celite with CHFI or Cytochrome-C prevented the activation of Factor XII and the subsequent activation of Factor VII and the PT. These studies demonstrate the importance of Factor XII in the cold activation of Factor VII and shortening of the PT and indicate that inhibitors to activated Factor XII or XII fragments are useful in inhibiting in vitro shortening of the PT. These findings suggest that the development of a collection tube that prevents contact activation also would inhibit adequately the cold-promoted activation of the PT and Factor VII.

Aprotinin

Pelvic neoplasia in Peutz-Jeghers syndrome.

A cervical adenocarcinoma, a left ovarian granulosa cell tumor, and a right ovarian sex cord tumor with annular tubules developed in a woman with Peutz-Jeghers syndrome. This apparent first report of three different pelvic tumors occurring in a patient with Peutz-Jeghers polyposis suggests a possible link between pelvic tumors and the Peutz-Jeghers syndrome.

Adenocarcinoma