Macrophage-colony stimulating factor (M-CSF) is increased in the synovial-like membrane of the periprosthetic tissues in the aseptic loosening of total hip replacement (THR)

Summary The aim of the study was to assess the eventual presence, cellular localization and extent of expression of the osteoclast activating cytokine M-CSF (CSF-1) in the periprosthetic tissues around loose total hip replacement (THR). Synovial-like membrane was obtained from the implant-to-bone interface and pseudocapsule from ten total hip revisions performed for aseptic loosening and compared to ten hip synovial tissue samples obtained from ten patients who had primary THR for osteoarthritis. Avidin-biotinperoxidase complex (ABC) and alkaline phosphatase-anti-alkaline phosphatase (APAAP) methods were used for staining and VIDAS image analysis for quantification. M-CSF was mainly produced by macrophages, which often contained wear particles, but also by some fibroblasts and vascular endothelial cells. The number of cells containing (per one mm² tissue) clearly increased in the interface (1585±212; p<0.01) and pseudocapsular (1456±248; p<0.01) tissue compared to synovial tissue (543±118). The present findings suggest, that inflammatory foreign-body type of response enhances expression of M-CSF in cases of aseptic loosening of THR. M-CSF produced in the synovial-like membrane in the implant-bone interface may contribute to activation of osteoclasts in periprosthetic bone and thus to loosening.     

Histochemical examination of energy metabolism in aortic vein grafts in rats

The duration of the presumed metabolic depression of syngeneic vena cava to aorta transplants was determined in rats and the site and type of energy metabolism in the vein grafts assessed. The aerobic metabolic activity was measured from the histochemical reactivity of the enzymes, succinate dehydrogenase and cytochrome oxidase, and the anaerobic activity by staining with lactate dehydrogenase. The activity of the hexose-monophosphate shunt was assessed by the histochemical demonstration of glucose-6-phosphate dehydrogenase. Sixteen hours after grafting a pronounced metabolic depression was noted. Recovery occurred 24 hours after transplantation. The most intense staining was from lactate dehydrogenase in the vein grafts and in the non-transplanted veins. At the end of the observation period of four months the grafts were definitely more strongly stained than the non-transplanted veins, with most of the activity in the thickened intima. This layer had a metabolic profile resembling that of the media of the adjacent aorta.     

Bone tissue concentrations of ciprofloxacin released from biodegradable screws implanted in rabbits skull

Previously, ciprofloxacin-releasing polylactide/polyglycolide 80/20 (SR-PLGA) screws have proven to be biocompatible with sufficient strength. However, there has been no information about the local concentrations of ciprofloxacin in bone tissue after their implantation. To measure bone concentrations of ciprofloxacin, two screws were implanted in each rabbit, one on either side of the sagittal suture (n = 28 rabbits). Follow-up periods were 2, 4, 8, 16, 24, 52 and 78 weeks. From each rabbit, bone blocks containing one screw were retrieved and used to measure drug concentration. Ciprofloxacin concentration at 2 weeks follow-up was 4.4 ± 4.2 μg/g, 14.1 ± 2.7 μg/g at 4 weeks and 7.6 ± 4.5 μg/g at 8 weeks. Measured concentrations were very low at 16 weeks (mean 0.09 ± 0.04 μg/g) and 24 weeks (mean 0.04 ± 0.02 μg/g). Surprisingly, the concentration was higher again at 1 year (mean 1.3 ± 1.0 μg/g). At 1.5 years, concentration had decreased again (mean 0.8 ± 0.6 μg/g). The drug concentration in bone tissue was higher than minimal inhibitory concentration of ciprofloxacin (Staphylococcus aureus 0.1–1.0 μg/g) at 2, 4, and 8 weeks. Ciprofloxacin-releasing SR-PLGA 80/20 screws could be used clinically for osteofixation and infection treatment in cranial bone.     

Replantation service in Helsinki University Central Hospital 1980-1985

A replantation service is a routine part of medical services. The best results are obtained when the work is centralized. In Finland five university hospitals have a replantation service. In the Helsinki University Central Hospital, 94 severed parts of the upper limb were replanted/revascularized in 1980-85. The amputation injury requiring replantation was most often a thumb avulsed by the driving axle of a tractor. The patients came from all over the country, and the short time span between the initial injury and admission to hospital--2.4 hours an average in 1985--shows that transport of these patients is not a problem in Finland. The mean duration of surgery was 6.9 hours. Most of the operations took place in the late afternoon, evening or at night. 16% of the cases needed immediate reoperation because of vascular problems. Later, over 40% of the cases underwent secondary procedures. Most of the patients returned to their former employment. In long-term follow-up, however, nine out of ten patients reported that the replanted organ was intolerant to cold. Therefore, with the exception of the thumb, single finger replantation should not be a routine procedure in a cold climate such as that encountered in Finland. A replantation service requires a minimum of four surgeons qualified in plastic surgery or hand surgery. The operating theatre will be in use through the night. Nurses, physiotherapists and occupational therapists must be specially trained. The surgeon must be prepared to perform multiple reconstructive procedures, both immediately and later on.     

Biochemical Changes in Bone Grafts Stabilized with Rigid Plates: I. Cancellous Grafts

The effect of rigid plate fixation on the chemical composition of cancellous interposition grafts was studied in rabbit tibio-fibular bones.

The concentrations of hexosamines and, to a lesser degree, of hydroxyproline and nitrogen, were high in the graft for the first 6 weeks, decreased from weeks 6 to 12, but remained higher than the corresponding values for the controls throughout the experiment (52 weeks). The ratio of hexosamines to hydroxyproline was highest for the graft at 3 weeks, indicating formation of cartilage and osteoid.

The initially low calcium concentration of the graft increased by 35 per cent from weeks 1 to 6, decreased from weeks 6 to 12, and remained below normal thereafter in comparison with corresponding values for the cortical host bone. The ratio of calcium to hydroxyproline increased throughout the experiment, reflecting maturation of the graft to lamellar bone.

Thus, biochemically the early incorporation of rigidly fixed cancellous interposition grafts resembles the healing of unimmobilized fractures by callus formation.     

Knee degeneration in concrete reinforcement workers.

The loads on the knees in concrete reinforcement work and maintenance painting were analysed on eight construction work sites. A total of 352 reinforcement workers and 231 painters. Finnish men aged 20-64, were clinically and radiologically examined to determine the condition of the knee joints in active workers. The loads on the knees and the occurrence of minor injuries and accidents were higher in reinforcement work than in painting, but the occurrence of symptoms, clinical signs, and radiological findings was equally common in both groups. Reinforcement work seemed to provoke more symptoms from degenerated knees than painting.     

Three cases of severe verapamil poisoning

Three cases of verapamil intoxication are described. The first two patients took 6.4 g verapamil each and the third one took 0.8 g of verapamil and alcohol. All three developed a third-degree atrioventricular dissociation, the first patient developed a slow idioventricular rhythm without atrial activity, the second a temporary asystole. All were hypotensive, had anuria and shock, the first two were unconscious for several hours. The first one was treated with artificial cardiac pacing, orciprenaline and calcium gluconate, the second with cardiac pacing and orciprenaline. The third patient received fluids and a dopamine infusion. In the first case sinus rhythm returned 31 h after the swallowing of tablets, in the second after 32 h and in the third after 10 h. Pacing with intensive monitoring and care seemed to be the most beneficial treatments in these cases.     

Assessment of microvascular clamping injury of rat aorta by histochemical examination of oxidoreductases

To assess clamping injury to the rat abdominal aorta, the activities of two oxidoreductases, lactate dehydrogenase (LD) and succinate dehydrogenase (SD), were estimated histochemically at various points in time after clamping the aorta for 30 min (group A) or 60 min (group B) with two kinds of microvascular clips. Areas of depressed LD and SD activity were found 3 days after surgery in group A and 1 day and 3 days after surgery in group B. The random, intermittent occurrence of the changes in enzyme activity within the time groups pointed to a mild trauma induced by the clips. At 1 week and thereafter, no changes in enzyme activities were observed in the aortic wall. Two different patterns of depressed enzyme activity were observed: One was a narrow zone without activity throughout the medial layer, and the other consisted of a broader area of depressed activity in the outer parts of the media. Occluding the aorta with a mosquito clamp led to tissue destruction and loss of enzyme activity in the injured area. This study shows that enzyme histochemistry provides nonquantitative methods to detect and localize microvascular injury and that the injury caused by the microvascular clips was mild and reversible.