Biomedical subjects

V Kusec

Publications and source records attributed to V Kusec.

At least 19 recordsLinked to original sources

PubMed2006

Comparison of the growth hormone, IGF-1 and insulin in cerebrospinal fluid and serum between patients with motor neuron disease and healthy controls.

Neurotrophic effects of the growth hormone (GH), insulin-like growth factor-1 (IGF-1) and insulin on the central nervous system have become more apparent in the past decade. In this study, we measured serum and cerebrospinal fluid (CSF) concentrations of GH, IGF-1 and insulin in 35 patients with motor neuron disease (MND) [24 patients with definite amyotrophic lateral sclerosis (ALS) and 11 patients with progressive bulbar palsy] and in 40 healthy controls. Levels of serum concentrations of GH and IGF-1 did not significantly differ between the MND patient group and the healthy controls, while the level of insulin was significantly decreased (P = 0.0033) in the MND patient group. However, levels of all three examined parameters in CSF were significantly lower in the MND group than in the healthy controls with the statistical significance for IGF-1 and insulin of P < 0.001. This finding has not been reported previously, and further investigations into its association with ALS should establish whether it can be used as an early marker of the disease, or whether it merely represents a consequence of ALS development.

Biomarkers↗

PubMed2004

Interleukin-6, transforming growth factor-beta 1, and bone markers after kidney transplantation.

The aim of this study was to investigate the relationship between interleukin 6 (IL-6), transforming growth factor (TGF)-beta 1, IL-6 soluble receptors, and biochemical parameters of bone turnover after kidney transplantation. Of 64 patients enrolled in the study, 19 received the kidney transplant 2 to 12 months before the study, and 45 within the previous 15 to 175 months. We measured IL-6, TGF-beta 1, intact parathyroid hormone (PTH) bone alkaline phosphatase (BALP), osteocalcin (OC), and procollagen type I propeptide (P1CP) concentrations in the serum, and deoxypyridinoline crosslinks (DPD) in the urine of the patients. In 16 patients in the first posttransplantation year, the concentrations of IL-6 (P = 0.02), TGF-beta 1 (P = 0.01), BALP (P = 0.0002), OC (P = 0.001), and DPD (P = 0.01) were significantly higher than in patients with longer posttranslation period. Statistically significant negative correlation was found between post-transplantation time and IL-6 (P = 0.04), BALP (P = 0.003), OC (P = 0.0009), P1CP (P = 0.03), and DPD (P = 0.01) concentrations. Repeated measurements of the investigated parameters in the first post-transplantation year showed a significant decrease only in TGF-beta I level. In all patients, IL-6 correlated positively with PTH (P = 0.0009) and DPD (P = 0.03), and IL-6 soluble receptor (IL-6 sR) with DPD (P = 0.03). A decrease in IL-6 and TGF-beta 1 concentrations that paralleled the decrease in bone turnover markers in the posttransplantation period indicated that IL-6 and TGF-beta 1 were probably involved in the bone turnover after kidney transplantation.

Adolescent↗

PubMed2003

Compressed homologous cancellous bone and bone morphogenetic protein (BMP)-7 or bone marrow accelerate healing of long-bone critical defects.

We studied 18 adult male New Zealand rabbits with a critical right-sided ulnar defect of 15 mm. In six animals the defect was grafted with homologous compressed cancellous bone, in six animals with homologous compressed cancellous bone including 300 micro g bone morphogenetic protein (BMP)-7 and in six animals with homologous compressed cancellous bone including 0.5 ml autologous bone marrow. The defect was studied using radiographs every second week for 10 weeks. At the conclusion of the experiment the animals were killed and the defect studied by histology and histomorphometry. In all animals treated with the addition of autologous bone marrow and in five of six animals treated with the addition of BMP-7, the defect healed. There was no union in animals treated with homologous compressed cancellous bone without additive. The histological picture of the regenerated area was similar in the two experimental groups. Woven bone contained small marrow spaces with fibrous tissue and capillaries. The osteoid seams were on average greater in animals that received autologous bone marrow as compared to animals that received BMP-7.

Animals↗

PubMed2002

Distraction osteogenesis by Ilizarov and unilateral external fixators in a canine model.

We studied distraction osteogenesis in canine experimental model using two types of external fixators, Ilizarov (n=6) or AO unilateral (n=9) external fixator. Distraction started 1 week after surgery (2 x 0.5 mm/day) and lasted for 3 weeks. Specimens were harvested from weeks 7 through 12. The outcome was assessed by X-ray, histology, histomorphometry and microradiography. Bone regeneration as observed by X-rays was satisfactory and similar in both groups. Both endochondral ossification and intramembranous ossification were found simultaneously in both groups. In both groups, bone formation parameters were significantly higher in the area of consolidating bone. No differences in histomorphometric parameters existed between the groups. In the study period, the bone formation was enhanced and prevailed in the distraction area. This study demonstrated the utility of the canine experimental model for the study of distraction osteogenesis.

Animals↗

PubMed2001

Osteogenesis imperfecta at the beginning of bone and joint decade.

Osteogenesis imperfecta (OI), or brittle bone disease, is a heritable disorder characterized by increased bone fragility. Four different types of the disease are commonly distinguished, ranging from a mild condition (type I) to a lethal one (type II). Types III and IV are the severe forms surviving the neonatal period. In most cases, there is a reduction in the production of normal type I collagen or the synthesis of abnormal collagen as a result of mutations in the type I collagen genes. These classic forms of OI are described in this review. There are instances, however, where alterations in bone matrix components, other than type I collagen, are the basic abnormalities of the OI. Recently, three such discrete types have been identified by histomorphometric evaluation (types V and VI) and linkage analysis (Rhizomelic OI). They provide evidence for the as yet poorly understood complexity of the phenotype-genotype correlation in OI. We also discuss bisphosphonates treatment as well as fracture management and surgical correction of deformities observed in the patients with OI. However, ultimately, strengthening bone in OI will involve steps to correct the underlying genetic mutations that are responsible for this disorder. Thus, we also describe different genetic therapeutic approaches that have been tested either on OI cells or on available OI murine models.

Animals↗

PubMed2000

The localization of the functional glucocorticoid receptor alpha in human bone.

Glucocorticoids have well-documented effects on the skeleton, although their mechanism of action is still poorly understood. The actions of glucocorticoids on bone cells are mediated, in part, directly via specific receptors. The presence of these receptors has been demonstrated in both rodent and human osteoblastic cells in vitro, but their presence in human bone in vivo has not been reported. In this study, we have used specific affinity purified polyclonal antibodies to the functional glucocorticoid receptor alpha (GRalpha) to investigate its expression in both developing and adult human bone using sections of neonatal rib, calvarial, and vertebral bones, tibial growth plates from adolescents, and iliac crest biopsies from adults who were to undergo liver transplantation. In the tibial growth plates, GRalpha was predominantly expressed in the hypertrophic chondrocytes within the cartilage. In the primary spongiosa, the receptor was highly expressed by osteoblasts at sites of bone modeling. Within the bone marrow, receptors were also detected in mononuclear cells and in endothelial cells of blood vessels. In the neonatal rib and vertebrae, GRalpha was widely distributed at sites of endochondral bone formation in resting, proliferating, mature, and hypertrophic chondrocytes. They were also highly expressed in osteoblasts at sites of bone modeling. At sites of intramembranous ossification in neonatal calvarial bone and rib periosteum, GRa was widely expressed in cells within the fibrous tissue and in osteoblasts at both the bone-forming surface and at modeling sites. In the iliac crests from adults, GRalpha was predominantly expressed in osteocytes. The receptors were not detected in osteoclasts. Our results show for the first time the presence of the functional GRalpha in human bone in situ and suggest that the actions of glucocorticoids on bone may be mediated, in part, directly via the GR at different stages of life. The absence of receptor expression in osteoclasts also suggests that the effects of glucocorticoids on bone resorption may be mediated indirectly.

Adolescent↗

PubMed2000

Histopathological features of gastritis before and after treatment for Helicobacter pylori.

AIM: To assess five main histological features of gastritis in gastric mucosa colonized with Helicobacter pylori before and after the treatment. METHODS: Histologic assessment of H. pylori-associated gastritis was performed according to the Sydney classification before and after the treatment in 97 patients. Two additional parameters - the presence of lymphocytic aggregates and coccoid forms of bacteria - were also analyzed. Helical and coccoid forms of H. pylori were detected by immunohistochemistry in biopsies after the treatment. RESULTS: Whereas acute epithelial damage was quickly repaired, some of the local responses to bacteria, e.g., lymphoid aggregates and intestinal metaplasia, persisted after treatment. Higher H. pylori and cocci density was found before and after treatment in patients with intestinal metaplasia (p=0.020). Correlation between H. pylori and mucosal atrophy was found only after treatment (p=0.009). Immunohistochemical staining was more sensitive in detecting of H. pylori than Giemsa staining (p=0.007) in cases where, using only Giemsa staining, it was not possible to distinguish coccoid forms of H. pylori from other cocci. CONCLUSION: After treatment, H. pylori-associated gastritis showed reduction of acute and chronic inflammation, but lymphoid aggregates and intestinal metaplasia persisted. Immunohistochemistry of different forms of H. pylori may be a valuable technique in monitoring the success of the treatment.

Amoxicillin↗

PubMed2000

Determinants of reduced bone mineral density and increased bone turnover after kidney transplantation: cross-sectional study.

AIM: To analyze bone metabolism and the risk factors of bone loss in kidney transplant recipients. METHODS: The bone mineral density (BMD) of the lumbar spine, femoral neck, and radius was determined by dual-energy X-ray absorptiometry in 52 patients 8 days to 228 months after kidney transplantation. Total and bone alkaline phosphatase (BAP), osteocalcin, procollagen, type I collagen telopeptide, collagen cross links, calcium, intact parathyroid hormone (iPTH), and creatinine were measured in all patients. RESULTS: The BMD of the spine and femoral neck was reduced in 57%, and of the radius in 72% of the patients. Reduced BMD was associated with significantly increased levels of iPTH, osteocalcin, and procollagen. Dialysis duration negatively correlated with the radius BMD in all patients and the femoral neck BMD in women. No relationship between BMD and length of post-transplantation time, age, cumulative steroid dose, or serum creatinine level was established. All biochemical parameters negatively correlated with the spine BMD, but not with the BMD of the femoral neck and radius. The correlation between BAP and telopeptide and length of post-transplantation time was also negative. No difference in the incidence of osteopenia was found between genders. CONCLUSION: Osteopenia/osteoporosis and increased bone turnover were present in more than a half of the kidney transplant recipients. Reduced BMD was associated with enhanced bone remodeling, primarily mediated by PTH hypersecretion. The length of post-transplantation period, cumulative steroid dose, gender, and age could not be identified as risk factors of reduced BMD.

Absorptiometry, Photon↗

PubMed1999

Human bone marrow osteoprogenitors express estrogen receptor-alpha and bone morphogenetic proteins 2 and 4 mRNA during osteoblastic differentiation.

Understanding the mechanisms that control the proliferation and commitment of human stem cells into cells of the osteogenic lineage for the preservation of skeletal structure is of basic importance in bone physiology. This study examines some aspects of the differentiation in vitro of human bone marrow fibroblastic cells cultured in the absence (basal media) or presence of 1nM dexamethasone and 50 micrograms/ml ascorbate for 6, 10, 14, and 21 days. Northern blot analysis and in situ hybridisation with digoxygenin-labelled riboprobes for Type I collagen, osteocalcin, bone morphogenetic proteins 2 (BMP-2), and 4 (BMP-4) and the estrogen receptor alpha (ERalpha), together with immunocytochemical analysis of ERalpha expression and histochemical staining of alkaline phosphatase was performed. In basal media, alkaline phosphatase activity and collagen expressions were detected at day 6, ERalpha from day 10 and osteocalcin from day 10. In the presence of dexamethasone and ascorbate, cell proliferation and alkaline phosphatase were markedly stimulated over 10 to 14 days with a dramatic increase in the temporal expression of Type I collagen, ERalpha, and osteocalcin mRNAs in these cultures. Northern blot analysis showed cells cultured in basal media, expressed the highest levels of the mRNA for each marker protein at day 14, whereas in the presence of ascorbate and dexamethasone, the highest levels for alkaline phosphatase, ERalpha, osteocalcin, BMP-2, and BMP-4 were observed at day 21. ERalpha, BMP-2, and BMP-4 expression were found to correlate temporally with induction of the osteoblast phenotype as determined by alkaline phosphatase, collagen, and osteocalcin expression. These results give additional information on the development of the osteoblast phenotype from early fibroblastic stem cells and on the biological factors involved in this process. These studies suggest a role for estrogen and BMP-2 and -4 in the differentiation of osteoprogenitor cells.

Aged↗

PubMed1999

Expression of estrogen receptor-alpha in cells of the osteoclastic lineage.

Estrogen deficiency at the menopause is associated with an increased rate of bone loss and subsequent risk of skeletal fracture. Whilst cells of the osteoblastic lineage are known to express estrogen receptors, the presence of estrogen receptors in osteoclasts remains controversial. We have examined expression of the classic estrogen receptor, estrogen receptor-alpha (ERalpha), during osteoclast differentiation. In situ mRNA hybridisation with a digoxygenin-labelled riboprobe to ERalpha mRNA, together with immunocytochemical analysis using a human ERalpha-specific monoclonal antibody demonstrated similar findings and confirmed the expression of ERalpha in chondroblasts and osteoblasts from human fetal bone and mineralising human bone marrow cultures. ERalpha expression was detected in human bone marrow cultures treated with 1,25(OH)2D3 and macrophage colony-stimulating factor and in macrophage cultures treated with 1,25(OH)2D3. However, in an in vitro model of human osteoclast formation, no ERalpha expression was observed in the osteoclasts that developed. The human preosteoclast TCG 51 cell line showed strong expression of ERalpha in contrast to the low levels observed in the more mature bone resorptive TCG 23 cell line. No expression was detectable in osteoclasts cultured from giant cell tumour of bone (GCTB) tissue or in osteoclasts in Pagetic, GCTB, or hyperparathyroid bone tissues. In conclusion, preosteoclasts express detectable levels of ERalpha, but osteoclast maturation and bone resorption is associated with loss of ERalpha expression. This indicates that ERalpha expression and regulation may play a role in osteoclast formation.

Bone Diseases↗

PubMed1999

The usefulness of biochemical bone markers in predicting the response of hormone replacement therapy in perimenopausal cigarette smoking healthy women.

The purpose of our study was to evaluate the effects of orally administered combined sequential estradiol (2 mg 17 beta estradiol) with progestin (1 mg norethisteron acetate) daily during ( +/- SD) 15.34 +/- 13.89 months on bone markers in perimenopausal cigarette smoking women. The control group consisted of cigarette smoking perimenopausal women without hormone replacement therapy (HRT). The following biochemical bone markers were analyzed in hormone replacement users (N = 35) and non-users (N = 28): serum total calcium (Ca), total alkaline phosphatase (ALP), procollagen I C-terminal propeptide (PICP), cros-linked carboxyterminal collagen I telopeptide (ICTP) and osteocalcin (OC). When we compared the results of bone markers in the cigarette smoking current users and non cigarette smoking non-users, we found statistically significant lower levels of bone formation markers, ALP and OC, and lower level of bone resorption marker; ICTP in users than in non-users. In perimenopausal cigarette smoking women on HRT lower levels of new biological markers reflected less intensive bone remodelling and probable decrease in bone loss than in non-users. These results indicate that the measurement of biological bone markers are useful to identify risk women for osteoporosis who may have special benefit from the treatment with hormone replacement therapy, even when they smoke.

Alkaline Phosphatase↗

PubMed1998

Biochemical parameters of bone turnover in kidney transplant recipients.

Impairment of bone remodelling due to chronic renal failure persists even after successful kidney transplantation. Bone turnover was assessed in 22 kidney transplant recipients by measurement of serum bone markers: total (tALP) and bone alkaline phosphatase (bALP), osteocalcin (OC), procollagen I C-terminal propeptide (PICP), collagen I C-terminal telopeptide (ICTP), and iPTH. The patients were on dialysis 56.6 +/- 43.1 months before transplantation (mean +/- SD) and 34.2 +/- 23.0 months had elapsed after transplantation. The bone markers were within the reference range in 23% of patients for iPTH, 73% for tALP and 82% for bALP, 41% for OC, 73% for PICP and 50% for ICTP. A positive correlation was found between dialysis duration and ICTP, and iPTH and bone formation markers (OC, bALP). The obtained results indicate that bone turnover was increased after kidney transplantation, with prevailing bone resorption, which seems to be influenced by dialysis duration.

Adult↗

PubMed1998

Localization of estrogen receptor-alpha in human and rabbit skeletal tissues.

Estrogen is essential for the development and maintenance of optimal bone mass in women and men, and acts through activation of estrogen receptors (ER). We have examined the pathways of estrogen action on the skeleton by seeking to localize the "classical" estrogen receptor, ER alpha, to particular cells to test the hypotheses that 1) estrogen directly influences growth plate chondrocytes; and 2) estrogen has a principal action on bone tissue via osteoblasts. ER alpha messenger ribonucleic acid (mRNA) was localized by in situ hybridization in human specimens from five males (11-15 yr old), two females (9 and 11 yr old), and three growing rabbits. In all of the human material examined, ER alpha mRNA was consistently identified in chondrocytes. In all of the rabbit tissue studied, ER alpha mRNA was localized in chondrocytes of the growth plate and the subarticular epiphyseal growth center. ER alpha mRNA signals were readily observed in both active osteoblasts and lining cells on trabecular surfaces of all samples. No clear evidence of positive staining was detectable in osteoclasts or osteocytes in either species. The distribution of ER alpha mRNA coincided with immunolocalization of the ER protein in the human specimens. These data suggest a direct action of estrogen on growth plate chondrocytes that may affect longitudinal growth and subsequent fusion of the growth plate and also on osteoblasts to affect bone formation at trabecular sites.

Adolescent↗

PubMed1998

Biochemical markers of bone metabolism in postmenopausal women--the effect of hormone replacement therapy and smoking.

AIM: Investigation of biochemical markers of bone metabolism in postmenopausal women with respect to hormone replacement therapy and smoking as a risk factor for osteoporosis. METHODS: Cross-sectional study of 107 healthy women receiving hormone replacement therapy (24 smokers) and 50 postmenopausal women (20 smokers) who served as a control group. The following biochemical parameters were analyzed in the serum: total calcium, inorganic phosphate, total alkaline phosphatase, procollagen I C-terminal propeptide (PICP), and cross-linked carboxyterminal collagen I telopeptide (ICTP). The effect of hormone replacement therapy and smoking on biochemical parameters was assessed by a two-way ANOVA. RESULTS: Significantly lower values of total calcium, inorganic phosphate, alkaline phosphatase, and ICTP in women on hormone replacement therapy compared to the control group indicated a higher rate of bone remodeling in the untreated postmenopause. In women smokers versus non-smokers, significantly lower values of only ICTP were found. Both hormone replacement therapy and smoking affected total calcium and phosphate levels, with the lowest values in non-smoking women on hormone replacement therapy and the highest in non-smoking control women. CONCLUSION: Reduction of bone turnover by hormone replacement therapy in menopause was indicated by lower values of biochemical parameters and collagen-related bone markers. Hormone replacement therapy is the prevalent factor affecting biochemical parameters, and probably conceals the possible effect of smoking.

Bone and Bones↗

PubMed1998

Changes in skeletal metabolism in pubertal girls can be revealed by biochemical parameters of calcium metabolism and bone turnover.

Biochemical changes related to skeletal turnover in puberty were investigated in a sample of 67 girls aged 8-14 years. The following biochemical parameters were measured in serum: total calcium, phosphate, magnesium, total alkaline phosphatase, osteocalcin, and calcium and hydroxyproline in the second morning urine. Thirty-five premenarchal girls (8-11 years) had significantly lower serum calcium, and higher alkaline phosphatase and phosphate than those menstruating regularly (N = 32, 12-14 years). A statistically significant negative correlation of serum parameters and age was found for phosphate and alkaline phosphatase in all subjects, and for calcium and magnesium only in the premenarchal girls. These results indicated the more intensive processes of skeletal metabolism occurring in prepubertal age and early puberty to reflect in basic biochemical parameters of calcium and bone metabolism. Analysis of correlation between biochemical parameters showed alkaline phosphatase and phosphate to correlate positively with hydroxyproline excretion and negatively with urinary calcium in all subjects. In the subjects after menarche, osteocalcin correlated with alkaline phosphatase and phosphate. Thus, biochemical parameters indirectly reflected physiologic changes occurring with bone turnover in puberty. Variations in bone turnover during puberty, including a more pronounced bone formation during prepubertal or early stages, can be indirectly observed through biochemical parameters related to calcium and bone metabolism. Investigations of skeletal growth and puberty would benefit from specific markers of bone remodeling and "basic" biochemical parameters, as it might disclose subtle metabolic relationships.

Adolescent↗

PubMed1997

The localization of androgen receptors in human bone.

Androgens have important effects on the human skeleton, and deficiency has been associated with bone loss in both males and females. The skeletal actions of androgens may be mediated directly via the androgen receptor (AR) or indirectly via the estrogen receptor after aromatization to estrogens. The presence of androgen receptors has been demonstrated in bone cells and chondrocytes in vitro, but their presence in human bone in situ has not been reported. In order to provide further evidence for a direct action of androgens on bone via androgen receptors, we have used specific monoclonal antibodies to investigate the expression of human AR in normal developing and osteophytic bone of both sexes. In the growth plates from the developing bone, androgen receptors were predominantly expressed in hypertrophic chondrocytes and in osteoblasts at sites of bone formation. They were also observed in osteocytes in the bone, and in mononuclear cells and endothelial cells of blood vessels within the bone marrow. In the osteophytes, androgen receptors were widely distributed at sites of endochondral ossification in proliferating, mature, and hypertrophic chondrocytes and at sites of bone remodeling in osteoblasts. They were also expressed in osteocytes and mononuclear cells within the bone marrow. The pattern and number of cells expressing the receptor was similar in both sexes. Our results show for the first time the presence and distribution of androgen receptors in normal developing human and osteophytic bone in situ and further provide evidence for a direct action of androgens on bone and cartilage cells.

Adenocarcinoma↗

PubMed1995

Bone turnover in homozygous beta 2-microglobulin knock-out mice does not differ from that of their heterozygous littermates.

beta 2-Microglobulin is a constituent of the class I major histocompatibility complex (MHC) molecule and crucial for its normal function in cell recognition. It has also been isolated from bone and shown to regulate bone metabolism and to be altered in various bone diseases. In order to further investigate the role of the immune system in bone metabolism, we studied basic properties of bone physiology in beta 2-microglobulin-deficient mice created by the technique of gene knock-out. Ten week-old male offspring homozygous (non-functional class I MHC molecule) or heterozygous (functional class I MHC molecule) for beta 2-microglobulin knock-out gene did not differ in the following measures of bone turnover: femur length, dry and ash weight and calcium content, serum calcium concentration and alkaline phosphatase activity, total vertebral tissue area, trabecular bone volume, osteid surface, osteoclast surface and mineral apposition rate. These data indicate that the bone turnover in beta 2-microglobulin-deficient mice is appropriate for the stage of their skeletal maturation.

Animals↗

PubMed1994

Osteocalcin reference range in a Croatian population sample.

Osteocalcin concentrations were measured in 40 healthy males and 60 healthy females aged 21-90 years by a commercial RIA kit. No significant difference between sexes was found for osteocalcin, and a negative and exponential regression with age existed only for females. In comparison to reference values of other investigators, higher osteocalcin concentrations were observed and considered consequential to sample selection and wide age range. Validity of the established reference range (1-18 ng/mL) was confirmed by measuring osteocalcin in patients with different bone metabolism disorders.

Adult↗