Jouko Viljanto

Is cellulose sponge degradable or stable as implantation material? An in vivo subcutaneous study in the rat.

The long-term behaviour of cellulose sponge implants, 10 x 10 x 5 mm in size, and tissue reactions in and around them were examined in the subcutaneous tissue of the rat from 1 to 60 weeks after implantation. The cellulose sponge used was filled up with connective tissue 4 to 8 weeks after implantation. Histologically, moderate foreign body tissue reaction inside the implant, the appearance of cracks and fissures, spotty colouration, and softening of the pore walls were observed up to 16 weeks after implantation. Later, the foreign body reaction inside the sponge became milder, the spotty colouration disappeared and micropores enlarged in the viscose cellulose matrix. Histomorphometrically, the cross-sectional area of the implants and the size of the pore wall fragments decreased, and the number of pore wall fragments increased significantly. The cellulose sponge used can be regarded as a slowly degradable implantation material. However, the time needed for the total disappearance of the cellulose sponge from subcutaneous tissue is longer than the 60 weeks.

Dupuytren's contracture: a review.

Abstract DC is a slow fibrotic process of the palmar fascia usually beginning in middle age in the form of small nodules at the distal ulnar aspect of one or both palms, gradually resulting in a permanent contracture of one or more fingers. The incidence varies between 1% and 3% of whites, and is six to ten times more frequent in males than in females. The etiology is unknown. Heredity certainly plays an important role, while local or distant trauma, neurogenic, and metabolic factors may be of significance in the development of this condition. Alcoholism, diabetes mellitus, and epilepsy are often associated with this moderately disabling ailment. Similar conditions of the plantar fascia may be seen isolated or concomitantly with DC of the hand. The natural history of DC varies greatly from one individual to another. Successful conservative treatment is possible only at the very beginning of the disease. Subsequently, various surgical methods should be considered. Whatever the method, recurrences are possible, especially in young people.

Cellstic: A device for wound healing studies in man. Description of the method

Abstract CELLSTIC is a miniature wound drain composed of a thin silicone rubber tube and a pressed rectangular stick of viscose cellulose sponge (VCS) placed inside the inner end of the tube. When moistened and placed between wound edges two sides of the sponge expand in opposite directions leaving two free channels between the remaining sides and the tube wall for the flow of wound exudate. Most cells in the exudate become attached to the sponge, where they may further invade, multiply and be transformed. The first human fibroblasts in the CELLSTIC sponge are usually seen three or four days after implantation. CELLSTIC does not disturb normal wound healing in any way even in newborn babies, as has been proved in 155 pediatric surgical patients. As well as being a testing device for human connective tissue regeneration in general, CELLSTIC may also be used to control the local effects of various medicines and radiotherapy on human wound healing.

Wound healing in children as assessed by the CELLSTIC method

Assessment of the quality and speed of wound healing in man has been rather difficult until the present time. By the use of CEELSTIC, a tissue-sensitive test drain composed of a standardized piece of viscose cellulose sponge inside a thin Silastic tube, cells existing between wound edges can be analyzed by histologic, cytologic, and enzyme histochemical means. The 166 pediatric surgical patients studied showed that wound healing is an age-dependent process reflected by the increased time needed for cellular transformation and maximal activation of hexokinase and isocitrate dehydrogenase with increasing age.

Evaluation of a New Cellulose Sponge-Tipped Swab for Microbiological Sampling: a Laboratory and Clinical Investigation

ABSTRACT A new type of swab (Cellswab; Cellomeda, Turku, Finland), utilizing a highly absorbent cellulose viscose sponge material, was compared to some traditional swabs. The survival of 14 aerobic and 10 anaerobic and microaerophilic bacterial species in the Cellswab, two commercial swab transport systems (Copan, Brescia, Italy, and Orion Diagnostica, Espoo, Finland), and one Dacron swab (Technical Service Consultants Ltd. [TSC], Heywood, United Kingdom) was evaluated. Bacteria were suspended in broth, into which the swabs were dipped. The Cellswab absorbed 1.3 times more fluid and released 3.5 times more fluid upon plating than the other swabs. Aerobic bacteria were stored in dry tubes, the others in transport medium, at 4°C and room temperature (RT), for up to 14 days. Swab samples were transferred to plates at 0, 1, 2, 4, 7, and 14 days. For 10 strains the Cellswab yielded ≥10% of the original CFU for longer than all the other swabs. In the clinical study, the ability of the Cellswab to detect beta-hemolytic streptococci from throat samples (n = 995) was compared to that of the TSC Dacron swab. The swabs performed equally, both when their samples were transferred to plates immediately and after storage for 1 day at 4°C or RT. The changes in normal microbiota after storage were also similar. The Cellswab was found to perform at least as well as ordinary swabs. It was better at storing fastidious strains, and at keeping bacteria viable for long storage times; it might well be a useful replacement or complement to ordinary swabs.

Correlation between interleukin‐6 and matrix metalloproteinase‐9 in early wound healing in children

Interleukin‐6 and matrix metalloproteinase–9 concentrations in the wound fluid and their associations to cellular changes were determined in early wound healing. Wound healing of 75 children who underwent elective operations was studied with the Cellstick® device, which was inserted into the wound at the end of the operation and removed 3 or 24 hours post‐wounding. Differential counts of the wound cells and interleukin‐6 and matrix metalloproteinase‐9 concentrations in the wound fluid were analyzed. Interleukin‐6 and the matrix metalloproteinase‐9 concentrations increased in parallel (r = 0.81). The proportion of wound neutrophils increased (p < 0.0001) and lymphocytes decreased (p < 0.0001) between the observation times. The number of wound neutrophils had a strong correlation with both interleukin‐6 (adjusted R2 = 0.41, p < 0.0001) and matrix metalloproteinase‐9 concentrations (adjusted R2 = 0.37, p < 0.0001). The extracellular matrix degradation process of the early wound healing seems to be closely linked to the inflammatory response. Both of these measured markers are associated significantly with the neutrophil proportion in the wound.

Macrophages in trauma‐induced myositis ossificans

The basic cellular mechanisms of different forms of myositis ossificans are poorly known. In the current experiment the nature of the early (24 168 h) inflammatory cell reaction preceding traumainduced myositis ossificans was studied. New bone formation was induced in the vastus intermedius region of the rabbit quadriceps muscle by means of immobilization and daily passive mobilization. Before the start of treatment, a cell harvesting device (viscose cellulose sponge in a silastic tube) was implanted in the region of interest. The opposite intermedius muscle and a standardized surgical skin wound served as the control sites. The results showed a significantly prolonged invasion of macrophages into the ossifying intermedius muscle as compared with the control intermedius muscle. It is hypothesized that microinjury and subsequent muscle necrosis cause the invasion of macrophages, and these cells respond to the conditions of the traumatized muscle under passive mobilization by releasing osteogenic growth factors.

Cranio‐caudal differences in granulation tissue formation: an experimental study in the rat

This study examined potential regional differences in the deposition of granulation tissue in cellulose sponges placed in the dorsum of rats. Four cellulose sponge implants, 10 × 10 × 5 mm in size, two in cranial and two in caudal positions, were used to induce granulation tissue formation in the back of the rat. A cranio‐caudal difference in connective tissue formation was assessed from 1 to 24 weeks after implantation. Granulation tissue ingrowth, measured histomorphometrically, was enhanced at 2 weeks and the surrounding capsule was thinner from 1 to 3 weeks in implants located in the cranial part of the back. In the cranial position, the number of fibroblasts, assessed semiquantitatively, was higher and the ratio of inflammatory cells to fibroblasts lower at 2–3 weeks. Also, the ratio of hydroxyproline content to total nitrogen content was higher after the first week in cranial specimens. Thus, a distinct cranio‐caudal difference in the proliferative phase was observed. These results show the obvious practical considerations underlying the need for randomization or comparison between implants from exactly corresponding cranio‐caudal locations.

Long-term follow-up of tissue reactions caused by Teflon paste and cross-linked collagen in rats

A 6-month follow-up study was carried out to compare local tissue reactions of polytetrafluoroethylene (Teflon paste) and cross-linked collagen (Zyplast), two injectable antireflux agents. Injections were made intradermally, intramuscularly, and into the bladder wall. Cross-linked collagen showed no foreign-body reaction. It maintained its original location and became well integrated with the surrounding tissue, forming an extra pad that was seen throughout the whole observation period. In contrast, Teflon caused a strong foreign-body reaction: single pearls of the agent became encapsulated within granulomatous tissue. However, a few pearls were seen still free with minimal surroundings several weeks after the injection. We conclude that both injectable agents cause a long-lasting reaction in rats that is strong enough to act as an extra support at the site of injection.

Local and systemic immune response to surgery under balanced anaesthesia in children.

We studied perioperative changes in the immune response and compared changes in the peripheral blood with those in the wound in 20 boys (0.5–3 years) during elective inguinal surgery under balanced anaesthesia. Blood samples were drawn before premedication, immediately, and 4 or 24 h after anaesthesia. Cells from the wound were harvested with the Cellstick device, removed from the wound 4 (n=10) or 24 h (n=10) after anaesthesia. We found decreased lymphocyte counts in the peripheral blood, increased percentages of activated T lymphocytes and B lymphocytes, and decreased percentages of total T lymphocytes, T helper cells and T cytotoxic cells. The percentages of T helper cells and B lymphocytes were lower in the wound than in blood. Mitogen‐induced lymphocyte proliferative responses decreased. This study demonstrates perioperative changes in the immune response in children and, as a new finding, that immune effector cells in the blood and in the wound are in a dynamic balance.