A New Approach to Percutaneous Subclavian Venipuncture to Avoid Lead Fracture or Central Venous Catheter Occlusion

Pacemaker and defibrillator leads and central venous catheters placed by commonly recommended techniques have been found to pass through the subclavius muscle, the costocaracoid ligament, or the costoclavicular ligament before entering veins medial to the first rib. Entrapment by these soft tissues subjects leads and catheters to stresses imposed by movements of the ipsilateral upper extremity. Accordingly, a new approach has been developed that introduces the lead or catheter into the subciavian vein near the lateral border of the first rib. This placement avoids soft tissue entrapment and may extend the longevity of leads and catheters.     

Review article: the dietary management of Crohn's disease

Enteral feeding has been shown to be as effective as primary therapy for Crohn's disease, but it requires high patient motivation, may be unpalatable and is expensive. However, in adolescents with growth failure and when corticosteroid therapy is contra-indicated or has failed, it may become the treatment of choice. Furthermore, dietary therapy allows circumvention of the adverse side-effects of repeated courses of steroids.
A number of different hypotheses have been proposed to explain the effect of enteral feeds but none has reached universal acceptance. Prospective trials suggest that the exclusion of whole protein is not necessary. Comparison of feeds with differing composition suggests that a low fat content increases efficacy and various explanations have been offered. The reduction of colonic bacterial load may also be important.
Because symptoms of Crohn's disease may be provoked by eating, there is a risk of falsely attributing symptoms to specific foodstuffs. However, in many individuals foods can be identified which affect disease activity, and their exclusion leads to prolongation of disease remission. Dietetic supervision during food testing is important to avoid detrimental effects on nutrient and micronutrient intake.     

The effects of aminosalicylic acid derivatives on nitric oxide in a cell-free system

Aims and Methods: To determine the effect of aminosalicylic acid derivatives on the concentration of nitric oxide produced in a cell-free system, by the use of a sensitive and specific polarographic meter. Results: The aminosalicylic acid derivatives 3-ASA (IC₅₀ 100 μm ), 4-ASA (IC₅₀ 350 μm ) and 5-ASA (IC₅₀ 5 μm ) all decreased the nitric oxide signal. These drugs had a similar inhibitory effect on the formation in vitro of nitrite from sodium nitroprusside (IC₅₀ 200 μm , 500 μm and 100 μm , respectively). Sulphasalazine (31.1 ± 5% decrease in signal at 1 mm ) was less effective than 5-ASA, but sulphapyridine, N-acetyl 5-ASA, indomethacin and hydrocortisone produced no decrease in nitric oxide signal at all. Conclusions: Nitric oxide binding may be part of the mechanism by which ASA derivatives exert their therapeutic effect, and this work suggests that it may be an important factor in the pathogenesis of ulcerative colitis.     

The use of azathioprine to ameliorate post-treatment encephalopathy associated with African trypanosomiasis

The treatment of human African sleeping sickness is complicated by a post-treatment meningoencephalitis that may be fatal. Using a mouse model this study assesses the use of the non-steroidal anti-inflammatory drug, azathioprine, in the management of this post-treatment reaction. Female NIH mice treated with the trypanocidal compound diminazene aceturate (40 mg/kg), 28 days after infection, developed a similar post-treatment reaction to that seen in humans. Administration of azathioprine (100 mg/kg) for 5 days before and 5 days after trypanocidal chemotherapy abrogated the pathology in the central nervous system although this returned approximately 15 days after cessation of azathioprine. Activated astrocytes associated with the later stages of the infection did not appear to be affected by the use of azathioprine.     

PHARMACOKINETICS OF ATRACURIUM AND LAUDANOSINE IN PATIENTS WITH HEPATIC CIRRHOSIS

The pharmacokinetic profiles of atracurium and one of its derivatives,laudanosine were studied following an i.v. bolus of atracurium0.6 mg kg^–1 administered to eight patients with hepaticcirrhosis and to seven healthy controls. The central volumeof distribution of atracurium was greater in the patients withcirrhosis (104.6 ml kg^–1) compared with the controls (69.6ml kg^–1) (P < 0.05), as was the total volume of distribution(281.8 ml kg^–1 and 202.1 ml kg^–1, respectively)(P < 0.05). There was no significant difference in the eliminationhalf-life of atracurium between the two groups. The total volumeof distribution of laudanosine was increased in cirrhotic patients(2.68 litre kg^–1) compared with healthy controls (1.97litre kg^–1) (P < 0.05), as was its elimination half-life(277 min in cirrhotic individuals; 168 min in controls) (P <0.05). There was no significant difference in the clearanceof laudanosine between the two groups.     

DECREASED BIOACTIVITY OF CIRCULATING PROLACTIN IN PATIENTS WITH RHEUMATOID ARTHRITIS

Growth hormone and prolactin (PRL) were measured by radio-immunoassayin sera of 36 patients with rheumatoid arthritis (24 femalesand 12 males) and of 50 normal blood donors (25 males and 25females). The bioactivity of PRL was also determined for bothgroups, using the Nb2 rat lymphoma proliferation assay. Althoughno significant difference was found between serum PRL valuesof patients and controls when determined by radio-immunoassay,the bioactivity of PRL was significantly decreased in patientssera, when compared to values obtained in age and sex-matchedcontrols. This decreased PRL bioactivity could not be attributedto drug treatments administered to the patients examined. KEY WORDS: Rheumatoid arthritis, Prolactin bioactivity, Prolactin immunoreactivity ^* Present address: Shaughnessy Hospital, 4500 Oak St., Vancouver,B.C., Canada. Present address: MRC Reproductive Biology Unit, 37 ChalmersSt., Edinburgh EH3 9EW, UK.     

ADENOCARCINOMA OF THE COLON AND ASSOCIATED NECROTIZING VASCULITTS OF MESENTERIC ARTERIES

Vasculitis associated with malignancy is uncommon, with themost well-known association being that between hairy cell leukaemiaand polyarteritis nodosa. The less common association of vasculitisand solid tumours usually involves a cutaneous leukocytoclasticvasculitis. We report a patient with Duke's C adenocarcinomaof the sigmoid colon with associated necrotizing vasculitisof the mesenteric arteries and postulate that local factorsmay predominate in its pathogenesis. KEY WORDS: Adenocarcinoma, colon, necrotizing vasculitis     

A NEW FOUR-PARAMETER THRESHOLD MODEL FOR THE PLASMA ATRACURIUM CONCENTRATION-RESPONSE RELATIONSHIP

The plasma concentration of atracurium and the electromyographicdepression of the first response of the train-of-four (T1:T0)were measured during and after recovery from a 10-min infusionof atracurium 0.25mg kg^–1 in 14 patients anaesthetizedwith 66% nitrous oxide and 0.9% isoflurane (end-tidal) in oxygen.A standard pharmacodynamic model was fitted to the data; a smallbut consistent discrepancy was found between the time and rateof onset of depression of the ratio T1:T0 and the predictionsof the standard biophase model of best fit to the data. Thisdiscrepancy is reduced by the inclusion of a threshold term(C_p:^ss) in the model to represent the greatest steady stateplasma concentration which would just fail to evoke an effect.The values of C_p^ss, correlated significantly with the valuesof C_p^ss₅₀(r=+0.627; P<0.02). The estimates C_p^ss₅₀ and k₆₀from the two models are very similar; the estimate of , theslope of the concentration-response curve, was less in the thresholdmodel. The relationship of the present threshold model to existingknowedge of neuro-muscular physiology is discussed.