Biomedical subjects

S Asko-Seljavaara

Publications and source records attributed to S Asko-Seljavaara.

112 records · Page 7Linked to original sources

PubMedDate not supplied

Compressive strength of calcium carbonate and hydroxyapatite implants after bone-marrow-induced osteogenesis.

Natural coral and structurally similar porous hydroxyapatite (HA) have been used as bone substitutes. They are not osteoinductive but bone formation can be induced by marrow cells, even in extraosseal sites. In our previous study we induced bone formation in porous coral and HA after having implanted the materials in intramuscular pockets in rat. New bone formed only in HA or coral implants soaked with marrow cells; fibrous tissue ingrowth alone was observed in the controls (without marrow). In the present study we examined the effect of tissue ingrowth on the mechanical properties of coral and HA implants obtained in a similar process to that used before. At 12 weeks the compressive strength of HA was higher in the marrow group than in the controls; it was also higher than that of the wet unimplanted material. The HA blocks did not show resorption. Coral resorbed quickly and lost its compressive strength, which was originally higher than in HA. At three weeks the marrow group was stronger than the control specimens. After six weeks only the marrow group, but not the controls, could be tested. Bone ingrowth seemed to maintain the strength of the coral implant even if it was dissolving. The mechanical strength of both materials was comparable to that of cancellous bone.

Animals↗

PubMedDate not supplied

Burn excision with contact neodymium: YAG laser.

The newest laser modality, the contact Neodymium: YAG laser, was compared with the standard steel scalpel in excisions of full-thickness burns. Six patients with deep burns of variable sizes were included in this pilot study. The area to be operated on in each patient was divided into two areas resembling each other as much as possible in size, tissue type, and depth of injury. The results suggest that bleeding was diminished by 44% in contact laser surgery compared with the steel scalpel. Still the difference was not significant. There was no impairment of graft take after laser surgery compared with the steel scalpel. However, the laser method caused a significant increase (p less than 0.02) in operating time. The contact Nd: YAG laser can be recommended for excision of relatively small deep burn injuries, especially in areas in which bleeding is a problem with other methods.

Adult↗

PubMedDate not supplied

Neuroendocrine carcinoma of the skin (Merkel cell carcinoma): ultrastructural and immunohistochemical demonstration of neurofilaments.

In this study we characterized a skin tumor that grew in the temporal region of a 69-year-old woman. On the basis of tumor morphology, a metastasis from a small cell carcinoma of the lung was initially suggested, but X-ray and bronchoscopic studies were negative. The tumor recurred twice within a year, yet no tumors were found elsewhere in the body. Ultrastructurally, cytoplasmic organelles compatible with neuroendocrine storage granules and perinuclear aggregates of intermediate-sized (8-10 nm) filaments were found in many tumor cells. Indirect immunofluorescence microscopy revealed neurofilament-type intermediate filaments in the tumor cells but no keratin- or vimentin-type filaments. Our results further demonstrate neural properties of this tumor type, which is generally considered to have its origin from Merkel cells, the cutaneous neuroendocrine cells.

Aged↗

PubMedDate not supplied

Granulocyte kinetics in burns.

Granulocytes, predominantly polymorphonuclear neutrophils, are the major components of the body's defense against acute infections. Starting from pioneering work done 20 years ago by Alexander and coworkers, neutrophil dysfunction after major thermal injury has been well documented. Defects in neutrophil function have been recognized as being serum-borne. Additionally, a review of granulocyte function in burns was presented in 1984, at the Conference on the Immune Consequences of Thermal and Traumatic Injuries. Because of methodologic difficulties, however, our knowledge of granulocyte kinetics has increased very slowly. Although the bone marrow produces 1.5 billion granulocytes per kg body weight per day and the marrow granulocyte reserve is enormous, the hematopoietic tissues, along with the release, distribution, and possible role of granulocytes in the pathophysiology of burns, have not been studied thoroughly. This article presents a current review of our knowledge of granulocyte kinetics in burns and the production and possible fate of granulocytes in tissues.

Agranulocytosis↗