Tγδ Cells and their Subsets in Blood and Synovial Tissue from Rheumatoid Arthritis Patients

We have examined the frequencies of T gamma delta cells in blood, synovial fluids, and synovial membranes of patients with rheumatoid arthritis (RA) and in blood from age-matched controls. Immunocytochemical and immunohistochemical techniques were used with monoclonal antibodies BB3 and A13 to define a major and minor blood subset of T gamma delta cells respectively. Together, these antibodies identify the majority (if not all) of the peripheral blood T gamma delta cells. Significantly lower levels of T gamma delta cells were found in the blood of RA patients compared with controls, whilst higher but not significant numbers were found in the synovial fluids of paired samples. Scattered T gamma delta cells were found only in some synovial membranes with a distribution similar to the T alpha beta cells. Analysis of the two different T gamma delta-cell subsets indicated a ratio of BB3 to A13 of about 5:1 in control and RA blood. However, this ratio was less than 1:1 in the RA synovial fluids and membranes. The migratory nature of the A13+ cells could account for their predominance in these sites. The possible pathological significance of these cells in the rheumatoid synovial fluid and synovial membranes is discussed.     

Gynopia in nursing practice: the case of urethral catheterization

• ? A pilot study of catheterized women was designed to investigate their perceptions of pain and discomfort during the procedure.
• ? The study aimed to test the feasibility of conducting a larger randomized controlled trial.
• ? Problems were encountered during the execution of the study, due to the need to conform to established principles in clinical research.
• ? Restrictions on access to patients impinged upon the opportunity to ‘cast the net wide’ in order to generate meaningful data.

     

In vitro oxyhaemoglobin saturation measurements in haemoglobin solutions using fibreoptic pulmonary artery catheters

We compared in vitro oxyhaemoglobin saturations using two pulmonaryartery catheters (catheter So₂) with oxyhaemoglobin saturations(So₂) measured by the IL282 co-oximeter and derived partialoxyhaemoglobin saturations (partial So₂) at different oxygentensions (Po₂) in six solutions: whole blood, 50:50 mixtureof whole blood and Plasmalyte A (haemodiluted blood), 50:50mixture of whole blood and 8% pyridoxylated haemoglobin-polyoxyethylene(PHP) conjugate (WB-PHP), 75:25 mixture of 8% PHP and PlasmalyteA solution (PHP66), 50:50 mixture of 8% PHP and Plasmalyte Asolution (PHP44) and stroma-free haemoglobin solution (SFH).Calculated P₅₀ values (Po₂, vs So₂) were 3.79, 3.58, 3.49, 3.15,3.04 and 2.07 kPa, respectively. However, if partial So₂ wasused the curves were shifted to the left, reducing P₅₀. CatheterSo₂ correlated well with So in whole blood (r² > 0.99 forboth catheters), haemodiluted blood (r² > 0.98 for both catheters)and WB-PHP solution (r² = 0.94 for both catheters). In PH P44(r² = 0.64 and r² = 0.57), PHP P66 (r² = 0.40 for the Oximetrixand r² = 0.25 for the Edwards catheter) and SFH solutions (r²= 0.33 for the Oximetrix and r² = 0.22 for the Edwards catheter)both catheters performed poorly. We conclude that mixed venousoxyhaemoglobin saturations measured by oximetric pulmonary arterycatheters are inaccurate in the presence of haemoglobin solutions.For accuracy a multi-wavelength co-oximeter should be used ifblood containing PHP or SFH is to be analysed. Present address: Department of Anaesthetics, Bristol Royal Infirmary,Bristol, UK     

Pulmonary Response to Toner upon Chronic Inhalation Exposure in Rats

Pulmonary Response to Toner upon Chronic Inhalation Exposurein Rats. MUHLE, H., BELLMANN, B., CREUTZENBERG, O., DASENBROCK,C., ERNST, H., KILPPER, R., MACKENZIE, J. C., MORROW, P., MOHR,U., TAKENAKA, S., AND MERMELSTEIN, R., Fundam. Appl. Toxicol.17, 280–299. A chronic inhalation study of a test tonerwas conducted by exposure of groups of F-344 rats for 6 hr/day,5 days/week for 24 months The test toner was a special Xerox9000 type xerographic toner, enriched in respirable-sized particlescompared to commercial toner, such that it was about 35% respirableaccording to the ACGlH criteria. The target test aerosol exposureconcentrations were 0, 1.0 (low), 4.0 (medium), and 16.0 (high)mg/m³. Titamum dioxide (5 mg/m³) and crystalline silicon dioxide(1 mg/m³), used as negative and pasitive controls for fibrogenicity,were also evaluated. Inhalation of the test toner or the controlmaterials showed no signs of overt toxicity. Body weight, clinicalchemistry values, food consumption, and organ weights were normalin the toner- and TiO₂-exposed groups, except for a 40% increasein lung weight in the toner highexposure group. All of the changesin the toner-exposed groups were restricted to the lungs orassociated lymph nodes. A chronic inflammatory response wasevident from the bronchoalveolar lavage parameters for the tonerhigh-exposure group. The incidence of primary lung tumors wascomparable among the three toner-exposed groups and the TiO²-exposed,and air-only controls, as well as consistent with historicalbackground levels A mild to moderate degree of lung fibrosiswas observed in 92% of the rats in the toner high-exposure group,and a minimal to mild degree of fibrosis was noted in 22% ofthe animals in the toner high-exposure group. The pulmonarychanges in the toner high-exposure group were smaller in magnitudethan those found in the crystalline silica-exposed group. Thecomparative fibrogenic potency of TiO², toner, and SiO² wasestimated to be 1:5:418 using a dasimetric model and assuminga common mechanistic basis. There were no pulmonary changesof any type at the toncr low-exposure level, which is most relevantin regard to potential human exposures The lung alterationsin the toner high-exposure group are interpreted in terms of"lung overloading," a generic response of the respiratory systemto saturation of its detoxification capacity. The maximum tolerateddose (MTD) criterion was met at the toner high (16 mg/m³)-exposurelevel.     

A STUDY OF INFLATABLE CUFFS ON ENDOTRACHEAL TUBES: Pressures exerted on the trachea

A simple method of measuring the pressure exerted by the cuffof an endotracheal tube on the trachea is described and hasbeen used to measure the pressures exerted by 16 commerciallyavailable cuffs on the wall of a model trachea. The Shiley,Portex soft-seal, Kamen-Wilkinson (Bivona Fome) tubes had thelowest tracheal wall pressures. Using this method in vivo thechanges in tracheal wall pressure exerted by a low-pressurecuff during percussion and vibration physiotherapy, and whenthe patient "fights the ventilator", were recorded.     

CARDIOVASCULAR EFFECTS OF KETAMINE IN THE PITHED RAT, RABBIT AND CAT

The effects of i.v. ketamine on arterial pressure and heartrate were examined in pithed rats, rabbits and cats. In allthree species ketamine caused a brief decrease in arterial pressureand heart rate. In the rat, but not in the other two species,this initial decrease in arterial pressure was followed by apressor response which was resistant to -adrenoceptor blockade,depletion of tissue noradrenaline stores and adrenalectomy.It is concluded that the peripherally mediated pressor responsefound in the pithed rat is specific to this species, is nota result of liberation of peripheral catecholamines and doesnot explain the pressor effect of ketamine found in man andseveral animal species. ^*Department of Pharmacology, University of Alberta, Edmonton,Alberta, Canada. Institute of Physiology, University of Glasgow, Glasgow G128QQ.