Paracetamol estimation: a new approach to reducing salicylate interference.

It is now well established that although acetylsalicylate does not interfere with the commonly used nitration method for measuring paracetamol, salicylate does interfere. Several methods have been used to remove this interference, by solvent extraction, or to make allowance for the interference, for example, by arithmetical correction. We describe a new approach to the problem by modifying the reaction conditions in an attempt to find the optimum conditions for the nitration of paracetamol while at the same time minimising salicylate interference. A method is proposed in which the concentration of nitrite is reduced and a time delay is introduced after the addition of sulphamic acid. This method is shown to be accurate, precise, and linear and exhibits minimal interference from salicylate.

On the transportability of linear discriminant functions.

Different methods can give different results for the same analyte, and inconsistent answers may be obtained if such results are used in linear discriminant functions. This is an important factor to consider when transporting linear discriminant functions from one laboratory to another; the example of alkaline phosphatase activity and the differential diagnosis of hypercalcaemia has recently been given. This study shows that results obtained by the method recommended by the Scandinavian Committee on Enzymes for alkaline phosphatase may be used in the calculation of the discriminant functions used for the differential diagnosis of hypercalcaemia and considers other factors that may affect the discrimination. It is concluded that, with care, linear discriminant functions may be transported from one laboratory to another.

Visiting bags: a labile thermal environment.

OBJECTIVE: To define usual colour and site of storage of visiting bags in general practitioners' cars and to investigate effect of these variables on temperature inside bag. DESIGN: Questionnaire to general practitioners; serial temperature measurements from paired black visiting bags at different storage sites and from bags of different colour. SETTING: South Devon coastal town during May and June. SUBJECTS: 200 general practitioners, of whom 145 returned legible questionnaires. MAIN OUTCOME MEASURES: Bag colour, duration and site of storage, temperature inside black bags at defined storage sites, and effects of bag colour on internal temperature. RESULTS: 111 (77%) of the general practitioners carried a black visiting bag, and 76 kept their bag in their car all day. The bag was coolest in the car boot, but irrespective of storage site, maximum internal temperature of the bag was always over 25 degrees C and reached up to 80 degrees C. Spraying a black bag silver significantly reduced the bag's internal temperature (mean difference 8.37 degrees C (95% confidence interval 6.68 to 9.86 degrees C) df = 59, t = 10.29, P < 0.001). CONCLUSIONS: General practitioners should use a silver coloured visiting bag; when visiting, they should store it in their car boot; at other times they should remove it to a cooler site.

Bilateral axillary and suprascapular neuropathy after coronary artery bypass surgery.

Neuropathies after coronary artery bypass (CABG) and cardiac surgery are usually transient and have been described fairly frequently. Our patient presented with an acute onset of a surprisingly symmetrical bilateral axillary and suprascapular neuropathy during the immediate CABG period (which to our knowledge has not been reported on before). The patient, aged 64 years, suffered from diabetes mellitus type 2 and hypertension, and underwent a triple CABG. Electroneuronographic and electromyographic examination confirmed the presence of the bilateral axillary and suprascapular neuropathy, which showed only minimal improvement 15 months later. The surmise is that the neuropathy developed as a result of compression or overstretching of the involved nerves during the surgical procedure, associated with suboptimal positioning of the arms. The 'hands-up position', with careful sternal retraction (Cooley retractor), may appear to prevent the posterior displacement of the shoulders and plexus injuries. The diabetes mellitus may have acted as an aggravating factor.

The Cardiothoracic Outreach Programme--a pilot project.

OBJECTIVE: To test the practicality, safety and benefits of major cardiothoracic surgery in two rural hospitals. DESIGN: Analysis of morbidity and mortality outcomes of a random collection of 35 patients, who underwent diverse surgical procedures. At each visit, the cardiothoracic team of Ga-Rankuwa Hospital-one surgeon, three registrars, two medical officers, six nurses, and four perfusionists-moved all equipment for major surgery, including bypass machines, to two small rural hospitals. Ga-Rankuwa Hospital, as a tertiary hospital attached to a medical school (Medical University of Southern Africa), mounted an outreach programme on a trial basis. The exercise was designed to render assistance, offer decentralised services, and test the skills of the cardiothoracic team in an environment where high-technology procedures have never been undertaken by the local health professionals. SETTING: Two rural hospitals, viz. Tintswalo and Mankweng, in the referral area of MEDUNSA, with no conventional ICU facilities. The support services for operative, pre-operative and postoperative care were very basic. The local personnel consisted only of general nurses and medical officers. None had experience of high-technology or complex theatre work. PARTICIPANTS: Thirty-five randomly selected patients of both sexes with ages ranging from 11 years to 64 years. Pre-operative diagnoses of diverse cardiac and lung conditions were made. The operations performed comprised 35 major procedures, including open heart operations and major lung procedures. The personnel comprised the MEDUNSA cardiothoracic team, who were assisted by local nurses. INTERVENTION AND OUTCOME: Thirty-five patients underwent 35 major procedures, all under general anaesthesia. Twenty cardiopulmonary bypasses were performed. There was 1 intra-operative death, due to low-output state. Intra-operative morbidity occurred in 2 of the 35 operations. These consisted of a cerebrovascular accident (CVA) (air embolism), and a temporary heart block. Late outcomes (after 1 week) were also analysed; the incidence was 1/35 operations. This was a CVA due to a left atrial appendage clot. Staff morale at the local hospital improved remarkably. The process of teaching the local professional nurses was surprisingly easy. Benefits included a decreased referral rate (100%), lower costs (transport, medicines, operations), excellent patient and community confidence in the work of the hospitals (increased hospital outpatient numbers), and political support (new tools, upgraded facilities and new equipment). RESULTS: The exercise was a resounding success in both measurable and general terms. All operations were successfully performed, with very low adverse outcomes (morbidity, mortality) and good quality of life for all the subjects. The safety and cost-effectiveness of cardiothoracic surgery under primitive conditions were demonstrated. The standard of patient care improved, and local staff acquired good basic skills in patient care. The referral patterns changed for the better and the confidence of the community in the services was enhanced. The risk/benefit ratio of the exercise was commendable. The feasibility of an extended service was encouraging.

Raised dopamine metabolites in a case of malignant paraganglioma.

This paper describes the case of a malignant retroperitoneal paraganglioma with extensive metastases. The patient presented with a supraclavicular mass and an absence of hypertension. Exclusively raised dopamine metabolites were detected which may be a marker of a malignant process and account for the lack of hypertension.

Absence of prolactin gene expression in colorectal cancer.

AIMS: Previous studies documenting hyperprolactinaemia in patients with colorectal cancer have suggested that the tumour is the source of hormone production. The aim of this study was to determine the frequency of hyperprolactinaemia in patients with colorectal cancer before, during, and after surgery, and also to determine whether prolactin is produced by these tumours. METHODS: Serum prolactin concentrations were measured in 20 patients with colorectal cancer before, during, and after surgical resection of their tumours. Samples taken during surgery included peripheral venous blood and blood taken from the main veins draining the tumour. To determine whether the tumour was responsible for the production of prolactin in these patients, paraffin wax embedded sections of tumour specimens were subjected to immunohistochemistry and western blotting using a monoclonal antibody to prolactin. RESULTS: Five patients (three women, two men) had preoperative prolactin concentrations above the normal reference range, although this increase was of clinical importance in only two. After surgical resection of their tumours, prolactin concentrations remained high in both patients. All 20 patients had greatly raised prolactin values at the time of surgery, irrespective of whether this was measured in peripheral blood or in blood taken from veins draining the tumour. All 20 colorectal cancer tissue samples, including those with raised preoperative and/or postoperative prolactin concentrations, were negative for prolactin staining. Frozen tissue was also available in four cases. The absence of prolactin gene expression in these four tumours was confirmed both by repeat immunohistochemistry and by western blotting. A further 50 colorectal cancer cases examined by immunohistochemistry alone were also unreactive for prolactin. CONCLUSIONS: The results of this study suggest that serum prolactin concentrations may occasionally be raised in colorectal cancer patients, but that the tumour is not the source of hormone production.