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Biomedical subjects

J Komender

Publications and source records attributed to J Komender.

At least 19 recordsLinked to original sources
PubMed2002

Bone mineral density in adolescent girls with anorexia nervosa--a cross-sectional study.

UNLABELLED: The total body and lumbar spine bone mineral density (BMD) were measured in order to determine the prevalence and possible risk factors of decreased BMD in anorexia nervosa (AN). SUBJECTS: Sixty-one in-patient girls with DSM III-R AN: age 14.7+/-2.16 years; duration of AN 12.9+/-15.1 months; percentage of ideal body weight 70+/-8.7%; body mass index score -1.62+/-0.79. METHOD: Total body (in 61 patients) and lumbar spine BMD (in 43 patients), content of lean and fat tissue mass were measured by DXA during the first month of treatment. RESULTS: Low total body BMD was found in 23.7% and low lumbar spine BMD in 36.6% of patients. There was a negative correlation between BMD and age, age of menarche, degree of undernourishment, duration of AN and amenorrhea. A step-wise linear regression analysis revealed that age of menarche was the most important factor related to BMD in this group.

Absorptiometry, Photon↗
PubMed2001

Bone mineral content and bone mineral density in adolescent girls with anorexia nervosa--a longitudinal study.

OBJECTIVE: Total body and lumbar spine bone mineral density (BMD-TB, BMD-L) and total body bone mineral content (BMC-TB) were measured to establish the course of bone demineralization in anorexia nervosa and the clinical factors influencing BMC-TB and BMD changes during treatment. METHOD: Forty-two girls with DSM III-R anorexia nervosa, age 14.7+/-2.4 years. BMC-TB, BMD-TB and BMD-L were measured in approximately 7-month intervals for 27.8+/-4.1 months using DXA. RESULTS: Despite nutritional improvement, there was an initial decrease of BMD-L, and no change in BMC-TB and BMD-TB. an increase in BMC-TB and BMD was observed after approx. 21 months from the beginning of the study. CONCLUSION: The improvement in BMC-TB and BMD was related to changes in nutritional status and was significantly marked in younger patients, with earlier anorexia onset and before menarche.

Adolescent↗
PubMed2001

Modification of collagen film by certain chemical agents.

Morphological changes and the content of free carboxyl groups in bovine collagen (type I) film under the influence of trypsin, hydrochloric acid (HCl) and ethylenediaminetetraacetic acid (EDTA) were studied. Incubation with trypsin and HCl was found to cause some delamination of the film and the appearance of some low-density spots. Incubation with EDTA did not cause any morphological changes. A high concentration of free carboxyl groups (10-fold higher than in control) was seen after incubation with trypsin.

Animals↗
PubMed2001

In vitro culture of human epithelial cells on a modified xenogenic collagen support.

Human epithelial cells (HeLa, HaCaT, NHK) were cultured in vitro on chemically modified collagen membranes. Adhesion to the support was measured by estimation of the percentage of adhering 51Cr-labeled cells. Proliferation was estimated with the XTT test. Morphological observations of cells growing on HCl-treated collagen were performed using histological and electron microscopic techniques. HCl and trypsin-modified xenogenic collagen was found to be a good support for human cells in vitro. EDTA-incubated collagen enhanced neither adhesion nor proliferation. The best adhesion and proliferation were found on HCl-treated collagen, depending, however, on the kind of cells.

Cell Adhesion↗
PubMed2000

Interaction between tissues and implantable materials.

Interaction between tissues and implantable materials is a factor of critical importance in biocompatibility studies. Bioactivity of implants is expected when the resorption or controlled integration of the implant with surrounding tissues is required. On the contrary, biomaterial inertness is suitable in the case of most load-bearing implants. Both desired and undesired consequences of partial implant biodegradation are discussed on the base of the authors' experimental work done on alumina and carbon-fiber-reinforced carbon composites (CFRC). Two examples of investigations of the interaction between bioceramics (CFRC, alumina, hydroxyapatite, and tricalcium phosphate) and cells in culture are shown as an alternative to the methods based on experimental implantation. The future of research on biomaterial-tissue interaction is discussed with respect to the developments in tissue engineering.

Aluminum Oxide↗
PubMed2000

The quality of heart valve tissue for homograft transplantation.

BACKGROUND AND AIM OF THE STUDY: The results of heart valve replacement surgery may be improved by refining surgical techniques and/or developing new heart valve transplants. The aim of this study was to examine the effect of age on the presence of cholesterol clefts and lipid deposits in the cusp base and sinus wall of aortic homografts. METHODS: Seventy-one valves were obtained at autopsy from donors (aged 15- 40 years) with no history of illness or evidence of serious illness. Trauma was the predominant cause of death among patients. The valves were examined using an osmium-vaporization technique. RESULTS: Osmiophilic deposits were detected in the cusp base in 28 cases (42%), and in the sinus wall in 49 cases (69%). Cholesterol crystals in the cusp base were found in 16 cases (24%), and sinus wall cholesterol clefts in 26 cases (38%). The model-predicted probability of cusp base lipid deposits existing was 76% in 40-year-old donors, 36% in 30-years-olds, and 11% in 20-year-olds; the probability of cusp base cholesterol clefts existing was 45%, 21% and 8% in these age groups, respectively. The influences of immunological reactions, biochemical changes (centers of calcification) and acceleration of atherosclerotic processes are discussed. CONCLUSION: The microscopic study of heart valves demonstrated the presence of lipid deposits in subjects of an unexpectedly young age. Among our study material, 58% of valves obtained from donors aged 11-40 years were unsuitable for transplantation. Our results confirmed the need for macroscopic inspection of heart valves before their being transplanted.

Adolescent↗
PubMed1999

Interaction between carbon composites and bone after intrabone implantation.

Candidate carbon fiber reinforced carbon (CFRC) porous implant materials were evaluated for tissue compatibility in a rat model. Six different CFRCs of constant pore size (about 30 microm) were fabricated that had 9, 12, and 17% porosity with 2-nm3 matrix crystallites and 6, 12, and 20% at 25 nm3. They were implanted as femoral transverse diaphyseal pins that were 1.5 mm in diameter. At 5 and 45 weeks, implant and bone histologic specimens were evaluated histologically and by a scanning electron microscope and an electron microprobe. Also, regional lymph nodes and spleens were examined. By 45 weeks, direct implant-bone contact was observed over most of the interface in most specimens. At the implant surface, there was partial replacement of CFRC with host tissue. However, the microprobe showed that the implant-bone interface was chemically abrupt with no cross-diffusion of ionic species. Besides the surface effects, there was partial filling of the implant pores with tissue, including bone organized de novo deep within. This was observed histologically and confirmed by microprobe. Lymph nodes and spleens were histologically normal, and no carbon particles were found. None of the results were influenced by porosity or matrix crystallite size over the ranges studied. In summary, these porous CFRCs are partially degraded when in contact with bone and appear substantially tissue compatible. They may be useful as scaffolds for regrowth of bone.

Animals↗
PubMed1999

Application of frozen and radiation-sterilised bone allografts for treatment of bone cysts.

Between 1981 and 1998 frozen and radiation sterilized bone allografts were transplanted into 1376 patients at the Institute of Traumatology, Orthopaedic and Neurosurgery of the Military School of Medicine in Warsaw. Of these 179 (13%) required treatment due to benign tumours. Incidence of solitary cysts was highest (127 cases, 71%), mainly occurring in children (84%). During surgery bone cysts were excised and filled by bone grafts. Results were evaluated several years after surgery (2-10 yrs) using x-rays and clinical examination. Rebuilding of allografts was one of the most important prognostic factors. Within the period of observation time 83% of transplanted allografts were rebuilt and substituted by own patients bone.

Adolescent↗
PubMed1999

Frozen and radiation-sterilized bone allografts in the treatment of post-traumatic malformation of bones.

Post-traumatical malformations of bone are often reconstructed with the use of preserved bone allografts. At the Institute of Traumatology, Orthopaedics and Neurosurgery 495 patients were treated with use of preserved (frozen and radiation-sterilized) bone allografts, following trauma, between 1981 and 1995. Non union of bone and osteomyelitis were main reasons for allotransplantation of bone. Remodelling of bone allografts has been observed during 2-8 years after surgery. Substitution of allografts and good result of treatment were found in 80% of all cases. In paper the analysis of results of treatment is presented.

Adolescent↗
PubMed1999

Fusion of spine in children scoliosis with frozen & radiation--sterilized bone allograft.

102 children have been treated at the Institute of Traumatology, Orthopaedics & Neurosurgery a result of scoliosis. In all of these multi-step treatment has been applied. Initially a telescopic rod was implanted into the spine. Allografts were introduced around the rod hook, after 6 or 8 months, when angle of scoliosis increased, the rod was exchanged for a longer one. The final step was performed when conditions permitted and the scoliosis was markedly corrected and the fusion of the spine with the solid allograft was accomplished. The result of treatment was evaluated 1 to 7 years after surgery. Bone allografts were rebuilt within 6 month. Correction of scoliosis of 50% to 70% was achieved in all cases.

Adolescent↗
PubMed1999

Human osteoblast in contact with various biomaterials in vitro.

OBJECTIVES: The aim of the study was to investigate changes in osteoblast number and viability in contact with biomaterials and to compare both tests. METHODS: Human primary culture osteoblasts were seeded on the polished surfaces of hydroxyapatite, alumina, titanium and surgical steel. After 4, 9, 14, 24 and 48h cultures were subjected to XTT viability assay. Subsequently Hoechst staining of nuclei was performed. Number of cells on each sample was counted. RESULTS: There were no differences in cell viability measured by means of XTT assay between osteoblasts cultured on hydroxyapatite and alumina during 48 hours of experiment. However on titanium as well as on surgical steel cell viability was significantly lower than on bioceramics. The lowest viability was noticed on surgical steel. Cell number on titanium was significantly higher than on steel. There were no differences between cell numbers on hydroxyapatite and alumina as well as between investigated bioceramics and metals. Nucleus number and the results of viability assay were compared. There was no correlation found between number and viability of cells. CONCLUSION: the results of a single test may not provide sufficient information on the interaction between cells and implant. Application of a battery of tests is necessary in material biocompatibility investigation in vitro.

Biocompatible Materials↗
PubMed1997

Catatonic syndrome preceded by symptoms of anorexia nervosa in a 14-year-old boy with arachnoid cyst.

This paper reports a case of a 14-year-old boy with arachnoid cyst in the right parietal region, who was referred to the child psychiatry department due to anorexia nervosa. A few days after admission he developed nihilistic and guilt delusions and lapsed into catatonia. The diagnostic problems and relations between his various pathological conditions (anorexia, catatonia, organic brain lesion) are discussed in this paper.

Adolescent↗
PubMed1997

Allogenic preserved costal cartilage in reconstructive surgery.

Allogenic, preserved cartilage is often used for reconstruction of face. This study was undertaken to analyze the effects of cartilage transplantation. In analyzed group of 437 patients after cartilage transplantation, 42.2% were operated because of posttraumatical changes, 29.0% because of congenital malformations. In 16.7% nonspecific inflammations were the cause of reconstructive operations. Malformations were mainly localised in nose 59%, ear concha 16.5% and mandible 10.9%. Human costal cartilage, preserved in 0.9% NaCl and radiation-sterilized was used for reconstruction. 24-190 months after surgery (in several clinical units) patients were examined and results were collected in special questionnaire by the team who performed surgery. The results of treatment were compared with age, diagnosis and localisation of changes. It was found that very good result of treatment was achieved in 33.5% of patients, in 41.8% result was satisfactory. In 19.9% of operated patients result of treatment was unsatisfactory. Correlation of some clinical and biological characteristics with the result of treatment is discussed.

Adolescent↗
PubMed1997

Long-term follow up after transplantation of frozen and radiation sterilized bone grafts.

The application of frozen and radiation sterilized allogenic bone grafts for reconstructions in orthopaedic operations is described. Analysis of results of treatment of 1125 patients was performed. It was found that use of preserved bone allows to reduce the extend and duration of surgery. Nearly total substitution of grafts may be seen in 3 to 8 months after surgery.

Adolescent↗
PubMed1996

Bone banking for transplantation in orthopaedic reconstructions.

Results of orthopaedic reconstructions in 1014 patients with the use of preserved allogenic bone grafts are presented. The method of grafts preservation seems to be of significance in surgical applications; deep-freezing is more favorable in more comparison with lyophilization. The result of treatment after bone transplantation is dependent on numerous biological and clinical variables.

Bone Diseases↗