Important role of CD18 in TNF-<Emphasis Type="Italic">α</Emphasis>-induced leukocyte adhesion in muscle and skin venules in vivo

OBJECTIVE: To examine the role of CD 18 in tumor necrosis factor-alpha (TNF-alpha)-induced leukocyte adhesion and extravasation in vivo. MATERIAL: Male wild-type (WT) and mutated mice with hypomorphic expression of CD 18. METHODS: Intravital microscopy was used to quantitate leukocyte-endothelium interactions provoked by TNF-alpha (0.5 microg) in the cremaster muscle and dorsal skin microcirculation. Tissue recruitment of leukocytes was evaluated in wholemounts of the cremaster muscle and in air pouches in the dorsal skin after TNF-alpha stimulation. RESULTS: TNF-alpha markedly increased venular leukocyte adhesion and recruitment in the cremaster muscle and skin in WT. Notably, in CD 18-targeted animals, leukocyte adhesion triggered by TNF-alpha challenge was significantly reduced by 58% and 72% in venules of the cremaster muscle and skin, respectively. Moreover, in CD18-mutants, tissue accumulation of polymorphonuclear leukocytes (PMNLs) provoked by TNF-alpha in the muscle and skin was decreased by 84% and 70%, respectively. Interestingly, the observed level of reduction in TNF-alpha-induced neutrophil adhesion and recruitment in CD18 gene-targeted animals corresponded well with the decrease in CD 18 expression on neutrophils from these mice, i.e. the surface density of CD18 was reduced by 77% in mutants compared to WT. Differential analysis revealed that the extravascular leukocytes comprised more than 90% PMNLs, indicating that neutrophils were the main inflammatory cell responding to TNF-alpha activation. Notably, the expression of CD18 increased by more than two-fold on extravasated neutrophils compared to circulating neutrophils in the peripheral blood both in WT and mutant animals. CONCLUSIONS: These findings suggest that CD18 is a dominant mediator of firm neutrophil adhesion to venular endothelial cells in the muscle and skin stimulated by TNF-alpha in vivo. In addition, this decreased adhesion in CD18-mutants attenuates leukocyte extravasation in response to TNF-alpha activation. Thus, inhibition of CD 18-function may provide an important strategy to inhibit leukocyte recruitment in cytokine-dependent diseases.     

On the Allocation of Cardiac Allografts from Blood Group-O Donors

An organ allocation policy, in which hearts from blood group-O donors are used to transplant recipients with other blood groups (ABO-compatible, non-identical transplantations), may affect blood group-O patients on the waiting list. We investigated how blood group affiliation influences potential recipients on the waiting list. In the case of patients with blood group O, fewer patients were transplanted, waiting list mortality was higher and waiting time to transplantation was longer. Patients with blood group O awaiting cardiac transplantation are affected considerably by an organ allocation policy in which ABO-compatible, non-identical transplantations are performed.     

OP-1 for cervical spine fusion: Bridging bone in only 1 of 4 rheumatoid patients but prednisolone did not inhibit bone induction in rats

We used OP-1 (also called BMP-7) on a collagen type-1 carrier in atianto-axial posterior fusions to promote bony healing after wire fixation. 4 patients who had instability between the atlas and axis due to rheumatoid disease received the implants. The patients were examined with conventional radiography postoperatively at 2, 6 and 10 months. In 3 patients, no new bone formation was detectable. In 1 patient, new bone bridged the fusion site at 6 months. 3 patients were on chronic steroid treatment, including the patient in whom bone formation was detected. To determine whether steroid treatment could be responsible for the low rate of bone induction, 24 rats each received OP-1 implants in an abdominal muscle pouch. They were divided into 3 groups receiving saline, 0.1 or 1.0 mg/kg BW of prednisolone daily until they were killed 3 weeks postoperatively. Specimens were decalcified for histology and the amount of calcium in the decalcifying solution was measured. All groups showed ossicles induced by OP-1, and no effect of prednisolone was detected. Thus the failures in the patients may have causes other than prednisolone treatment.     

The prevention of arterial collaterals after repeated temporary blockade of the hepatic artery in pigs

Hepatic dearterialization and permanent hepatic artery ligation can induce tumor necrosis but only of limited duration, partly due to a rapid development of arterial collaterals. The aim of this study was to determine if collateral formation could be reduced or prevented by repeated, transient dearterialization.Three groups of pigs were repeatedly and transiently dearterialized daily for 2 hours (n=5), 4 hours (n=5), and 6 hours (n=4), respectively, over a 4-week-period by means of a totally implantable vascular occluder described earlier by us. These pigs were compared with a group having permanent hepatic dearterialization (n=4). An additional group (n=3) served as a control and did not have dearterialization. After 4 weeks of treatment, hepatic angiograms were taken and absolute hepatic arterial blood flow was measured according to the reference sample method with radiolabeled microspheres. There were no demonstrable collaterals in the 2-hour group, formation of some small collaterals in the 4-hour group, and a fully developed collateral network in the 6-hour group, with similar findings in the permanently dearterialized group. Absolute hepatic arterial blood flow was significantly lower in the 4-hour group with obstructed hepatic artery compared to permanent hepatic dearterialization (p<0.01, Wilcoxon rank sum test) and highly significantly lower in the 2-hour group (p<0.0001, Wilcoxon rank sum test). Thus, repeated and brief dearterialization seems to prevent the formation of arterial collaterals and makes repeated arterial ischemia of the liver possible which could be of value in the treatment of liver tumors. In addition, a patent artery makes continuous intra-arterial cytostatic infusion possible.

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Resumen La desarterialización hepática y ligadura permanente de la arteria hepática puede inducir necrosis tumoral, pero sólo de duración limitada, en parte debido al rápido desarrollo de colaterales arteriales. El propósito de este estudio fue determinar si la formación de colaterales puede ser reducida o evitada mediante desarterializaciones repetidas y transitorias.Tres grupos de cerdos fueron sometidos a desarterialización repetida y transitoria por periodos de 2 horas (n=5), 4 horas (n =5), y 6 horas (n=4), respectivamente, en un periodo de 4 semanas, por medio de un método de oclusión vascular previamente descrito por nosotros. Estos cerdos fueron comparados con un grupo que había sido sometido a desarterialización hepática permanente (n=4). Un grupo adicional (n=3), no sometido a desarterialización, sirvió como control. Después de 4 semanas de tratamiento se tomaron angiogramas hepáticos y el flujo arterial hepático absoluto fue medido por medio del método de microesferas radiomarcadas. No se encontraron colaterales demostrables en el grupo de 2 horas, se observó la formación de algunas colaterales pequeñas en el grupo de 4 horas, y se observó el desarrollo de una bien formada red de colaterales en el grupo de 6 horas, con hallazgos similares en el grupo de desarterialización permanente. El flujo arterial hepático absoluto apareció significativamente menor en el grupo de 4 horas con la arteria hepática obstruída en comparación con los animales con desarterialización hepática permanente (p<0.01, prueba de adición del rango de Wilcoxon) y significativamente menor en el grupo de 2 horas (p< 0.0001).Por consiguiente, la desarterialización breve y repetida parece evitar la formación de colaterales arteriales y hace posible realizar la isquemia arterial repetida del hígado, lo cual puede ser útil en el tratamiento de los tumores del hígado. Además la presencia de una arteria hepática permeable permite la infusión intraarterial continua de agentes citostásicos.

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Résumé La désartérialisation hépatique ou la ligature permanente de l'artère hépatique peut provoquer des phénomènes de nécrose mais leur durée est limitée en raison du développement rapide d'une circulation artérielle collatérale. Le but de cette étude est de déterminer si la formation du réseau collatéral peut être réduite ou empêchée par désartérialisations intermittentes répétées.Trois groupes de cochons ont été respectivement soumis quotidiennement à cette méthode pendant 2 heures (n=5), 4 heures (n=5), et 6 heures (n=4) pendant une période de plus de 4 semaines à l'aide de l'appareil occlusif implantable décrit antérieurement par les auteurs. Ces animaux ont été comparés à un groupe de cochons (n=4) soumis à une désartérialisation hépatique permanente. Enfin un dernier groupe (n=3) d'animaux qui n'ont pas subi de désartérialisation a constitué un groupe de contrôle. Après 4 semaines des angiogrammes hépatiques ont été pratiqués et le flux sanguin artérial hépatique global a été mesuré à l'aide de microsphères radio marquées. Les constatations furent les suivantes: absence de collatérales dans le premier groupe, formation de quelques collatérales dans le second, réseau complet de collatérales dans le troisième identique à celui observé chez les animaux soumis à une désartérialisation permanente. Le flux artériel hépatique fut significativement plus bas dans le second groupe (4 heures) par rapport au groupe soumis à une désartérialisation permanente (p<0.01, test de Wilcoxon) et encore plus bas dans le premier groupe (p<0.0001, test de Wilcoxon).En conséquence il semble que la désartérialisation brève et répétée empêche la formation de collatérales artérielles en provoquant une ischémie artérielle répétée susceptible d'exercer une action utile dans le traitement des tumeurs du foie. En outre la préservation de la perméabilité artérielle permet l'injection continue intra-artérielle d'agents cytostatiques.

     

Renal function following kidney transplantation in children treated with cyclosporine

The study was performed to evaluate the longterm renal function of children treated with cyclosporine after kidney transplantation. Renal function was determined with clearances of inulin and aminohippurate sodium for evaluating glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Thirty-six children aged 0.4–16.2 (median 6.9) years at transplantation were examined within 5 months of transplantation and then yearly over 0.3–7.1 years. Twenty-five children and young adults, 1.5–20 (median 7.7) years of age, with solitary kidneys because of renal agenesis or nephrectomy, served as controls. The GFR and ERPF within 1 year of transplantation were significantly lower than those of controls (65±19 and 345±88 vs 96±12 and 474±91 ml/min per 1.73 m², respectively). GFR remained constant 4 years after transplantation, but ERPF decreased significantly. Significant inverse correlations were found between GFR within 5 months of transplantation and the mean cyclosporine concentration and the number of rejection episodes. The frequency of hypertension decreased from 82% within 5 months of transplantation to 0% after 4 years. The absolute GFR increased during follow-up. In conclusion, kidney transplantation results in a reduced renal function compared with that of solitary native kidneys. The reduction in renal function correlated with the number of rejection episodes and the cyclosporine load. The increase in absolute GFR during follow-up suggests a remaining capacity for growth and/or compensatory hypertrophy.     

Glucose utilisation in the lungs of septic rats

Sequestration and degranulation of leucocytes in the pulmonary microcirculation is considered to be a key event in the development of acute respiratory distress syndrome in patients with sepsis. Glucose serves as the main source of energy in activated leucocytes. The aim of this study was to assess whether glucose utilisation in the lungs can be used as an indicator of pulmonary leucocyte accumulation in an experimental model of sepsis of intra-abdominal origin. Sepsis was induced in rats by abdominal implantation of a gelatine capsule containing bacteria and rat colonic contents. Empty gelatine capsules were implanted in control animals. Animals were studied 6 and 12 h after sepsis induction. Glucose utilisation was measured as the tissue uptake of fluorine-18-fluorodeoxyglucose (¹⁸FDG) 1 h after intravenous injection of the tracer. Micro-autoradiography was also performed after injection of tritiated deoxyglucose. We found increased uptake of ¹⁸FDG in the lungs of septic animals. The uptake also increased with time after sepsis induction. ¹⁸FDG uptake in circulating leucocytes was increased in septic animals compared with controls, and micro-autoradiography showed intense accumulation of deoxyglucose in leucocytes in the lungs of septic animals. We conclude that glucose utilisation is increased in the lungs of septic rats. Measurements of pulmonary glucose utilisation as an index of leucocyte metabolic activity may open new possibilities for studies of the pathophysiology of sepsis and for evaluation of therapeutic interventions. Received 15 February and in revised form 28 April 1999     

Elevated prostate specific antigen and reduced 10-year survival among a cohort of Danish men consecutively referred from primary care to an urological department during 2005–2006

It remains unclear whether total prostate specific antigen (tPSA) or complex PSA (cPSA) has the best diagnostic performance. Additionally, the utility of percentage free PSA (%fPSA) is still debated. Our objectives were to compare the diagnostic performances of tPSA, cPSA, and %fPSA among patients referred from GP to an Urological Specialist and to investigate prognostic factors and survival in the cohort. A total of 1261 consecutive male patients without previously known prostate cancer (PCa) were referred to the same Department of Urology during June 2005 to August 2006. Some 299 patients were diagnosed with PCa and 962 patients were found without PCa. Among the PCa patients, the median age, tPSA, cPSA, and %fPSA levels were 70.8 years, 13.4?μg/L, 10.8?μg/L, and 12.6%. For patients without PCa the results were 67.5 years, 2.5?μg/L, 1.9?μg/L, and 24.9%. The sensitivity, specificity, PVpos, PVneg, and efficiency of tPSA and cPSA were overlapping (p?>?.05). In the tPSA interval >4?μg/L –?≤20?μg/L, %fPSA excluded PCa with a PVneg of 72.4%; 38.5% of PCa patients had a tPSA concentration >20?μg/L at the time of referral and these patients had a reduced 10-year survival as compared to patients with tPSA concentrations ≤20?μg/L. In conclusion, tPSA and cPSA showed similar diagnostic performances. %fPSA provided additional diagnostic information at tPSA concentrations >4?μg –?≤20?μg/L. The high percentage of patients with tPSA concentrations >20?μg/L indicate delayed use of tPSA resulting in advanced disease at presentation and reduced patient survival.     

Further studies on the cardiomegaly induced by beta-adrenoceptor agonists

Rats received continuous infusions of beta-adrenoceptor agonists by means of Alzet osmotic minipumps implanted subcutaneously. After 7 days of isoprenaline infusion (2 mg/kg per day) the heart/body weight ratio increased about 40 per cent compared with placebo treatment. The difference persisted after freeze-drying indicating a true hypertrophy and not merely an oedema. When terbutaline (20 mg/kg per day) was substituted for isoprenaline, the increase in wet weight ratio reached only about 5 per cent. Procaterol (2 mg/kg per day) and pirbuterol (20 mg/kg per day) had no effect on the heart weight. It is concluded that in doses expected to cause comparable stimulation of beta 2-adrenoceptors the unselective agonist isoprenaline is able, more than the beta 2-selective agonists terbutaline, procaterol and pirbuterol to cause cardiac hypertrophy thus indicating the involvement of beta 1-adrenoceptors.