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A Kreicbergs

Publications and source records attributed to A Kreicbergs.

At least 19 recordsLinked to original sources
PubMed2004

Differential bone turnover in an angulated fracture model in the rat.

We have developed a simple rat model of angulated tibial fracture which elicits substantial differences in bone formation and resorption within the same bone. In 35 rats the right mid-tibia was manually fractured and fixed with an intramedullary 17-gauge cannula needle. Twenty tibias were fixed in anterior angulation (27 +/- 5 degrees) and 15 in posterior angulation (31 +/- 5 degrees). Serial X-rays were taken over a 12-week period. All fractures healed completely within five weeks. In both groups, bone thickness was already significantly greater on the concave side than on the convex side at week 3 and remained so until the end of the experiment. The thickness on the convex side decreased dramatically within 3 to 5 weeks and gradually thereafter. For morphological analysis of bone mineralization, 3 rats from each group were given calcein and alizarin red injected at different time points up to 14 weeks. Maximum new bone formation was noted within the first 3 weeks. Over the ensuing weeks, new bone formation remained intense on the concave side, but it was virtually absent on the convex side. These results show that angulated fracture deformity reproducibly exhibits differential bone turnover, which can be exploited in research on local regulatory factors. To exemplify the utility of the model, an immunohistochemical study on two local markers was done. Callus tissue of five rats in the anterior angulation group at week 3 post-fracture was stained for the cytokine IL- 1beta, a stimulator of bone resorption, and the neuropeptide CGRP, an inhibitor of resorption, showing clear differences in positive staining between the concave and convex sides. Our in-vivo model offers a means of analyzing morphologically and quantitatively the differential expression and action of factors involved in local bone turnover.

Animals↗
PubMed2003

Purification and quantification of opioid peptides in bone and joint tissues--a methodological study in the rat.

The occurrence of methionine-enkephalin-Arg(6)-Phe(7) (MEAP) and dynorphin B (DYNB) representing two main precursors of opioids was analyzed in specimens from rat cortical bone, periosteum, bone marrow and joint tissue by radioimmunoassay (RIA). MEAP and DYNB were extracted in a solution of 4% EDTA in 2 M acetic acid previously proven suitable for extraction of sensory and autonomic neuropeptides in bone and joints. In crude extracts of cortical bone, the immunoreactive (ir) levels of both opioids were under the detection limit of RIA. As for DYNB this also applied to crude extracts of joints and periosteum. Therefore, two purification methods were tested and compared, i.e. reverse phase C 18 and ion exchange chromatography. RIA of the elution fraction disclosed a significant difference between the two methods in terms of recovery, i.e. <5% and 50%, respectively. Thus, purification by ion exchange chromatography prior to RIA appeared to be the most suitable by providing measurable levels of both MEAP and DYNB in all tissues analyzed (highest in bone marrow, lowest in cortical bone). The described method offers a means of quantifying opioid peptides in bone and joints, which may be utilized in the analysis of regulatory mechanisms of nociception, growth and immune responses in different conditions.

Animals↗
PubMed2003

Skeletal changes in type-2 diabetic Goto-Kakizaki rats.

We characterized appendicular and axial bones in rats with type-2 diabetes in five female Goto-Kakizaki (GK) rats, a strain developed from the Wistar rat showing spontaneous type-2 diabetes, and five age- and sex-matched non-diabetic Wistar rats. The humerus, tibia, metatarsals and vertebral bodies were analysed by peripheral quantitative computerized tomography (pQCT). In diabetic rats, the height of the vertebral bodies and length of the humerus were decreased while the length of the metatarsals was increased. A decreased cross-sectional area was found in the vertebral end-plate region and the tibial metaphysis. Notably, the diaphysis in all long bones showed expansion of periosteal and endosteal circumference. In tibia this resulted in increased cortical thickness, whereas in humerus and metatarsal it was unchanged. Areal moment of inertia was increased in all diaphyses suggesting greater bending strength. The most conspicuous finding in diabetic rats pertained to trabecular osteopenia. Thus, trabecular bone mineral density was significantly reduced in all bones examined, by 33-53%. Our pQCT study of axial and appendicular bones suggests that the typical feature of diabetic osteopathy in the GK rat is loss of trabecular bone and expansion of the diaphysis. The loss of metaphyseal trabecular bone if also present in diabetic patients may prove to underlie the susceptibility to periarticular fracture and Charcot arthropathy. The findings suggest that the risk of fracture in diabetes varies according to the specific sub-regions of a bone. The approach described may prove to be useful in the early detection of osteopathy in diabetic patients who may be amenable to preventive treatment.

Animals↗
PubMed2001

Autonomic innervation of tendons, ligaments and joint capsules. A morphologic and quantitative study in the rat.

We analyzed the neuronal occurrence of autonomic transmitters; noradrenaline (NA), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), in the Achilles tendon, medial and lateral collateral ligaments and knee joint capsule in the rat--by immunohistochemistry (IHC). In addition, the tissue concentrations of the sympathetic neuropeptide, NPY, and the parasympathetic peptide, VIP, were determined by radioimmunoassay (RIA). IHC demonstrated nerve fibers containing sympathetic vasoconstrictors--NA and NPY--and the parasympathetic vasodilator, VIP, in all tissues. NPY- and NA-positive nerve fibers were predominantly observed in larger blood vessels, whereas, nerve fibers immunoreactive to VIP were found in smaller vessels. In many nerve fibers a co-localization of the transmitters was seen. RIA showed that the concentration of NPY compared to VIP was 15-times higher in ligaments and twice as high in tendons and capsules. The differences noted may reflect a difference in vulnerability to degenerative conditions. In pathological conditions, dysregulation of autonomic transmitters in hypovascularized tissues subjected to repetitive mechanical load may contribute to tissue hypoxia leading to degeneration and rupture of tendons and ligaments.

Achilles Tendon↗
PubMed2001

Diagnosis of skeletal lymphoma and myeloma by radiology and fine needle aspiration cytology.

Diagnosis of skeletal lymphoma and myeloma by radiology and fine needle aspiration cytology From 1986 to 1998, all patients referred to Karolinska Hospital because of a skeletal destruction of unknown origin routinely underwent radiographic examination and fine needle aspiration cytology (FNAC). Among these, there were 83 patients with solitary lesions of the bone diagnosed and treated for myeloma (plasmacytoma) or non-Hodgkin's lymphoma. Review of the series showed that myeloma could not be distinguished radiographically from lymphoma. Nor could low and high grade lymphoma lesions be discriminated by radiographic appearance. The diagnostic utility of plain radiography in the two conditions seems to be confined to the mere detection of a destructive bone lesion and visual guidance for FNAC. The latter aspect, however, is crucial for the application of FNAC to bone lesions. Review of the cytologic specimens obtained by FNAC showed that they allowed a conclusive diagnosis in all 40 myeloma cases and in 41 of 43 lymphoma cases. In 32 of the 40 myeloma cases, the FNAC material could be used for immunocytochemistry, which disclosed kappa or lambda light chain restriction, corroborating the cytomorphological diagnosis. Thirty-eight lymphomas were characterized immunologically and in 35, a light chain restriction could be demonstrated. Our results show that the use of FNAC in the diagnosis of primary myeloma and lymphoma of bone obviates the need for other diagnostic modalities, including open biopsy. A combined approach based on radiology and FNAC, performed as an out-patient procedure, offers rapid and accurate diagnosis of myeloma and lymphoma among patients with radiographically unclassified destructive bone lesions.

Adolescent↗
PubMed2001

An opioid system in connective tissue: a study of achilles tendon in the rat.

The occurrence of endogenous opioids and their receptors in rat achilles tendon was analyzed by immunohistochemistry (IHC), radioimmunoassay (RIA), and in vitro binding assays. The investigation focused on four enkephalins, dynorphin B, and nociceptin/orphanin FQ. Nerve fibers immunoreactive to all enkephalins (Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg-Gly-Lys, Met-enkephalin-Arg-Phe) were consistently found in the loose connective tissue and the paratenon, whereas dynorphin B and nociceptin/orphanin FQ could not be detected. The majority of enkephalin-positive nerve fibers exhibited varicosities predominantly seen in blood vessel walls. Measurable levels of Met-enkephalin-Arg-Phe and nociceptin/orphanin FQ were found in tendon tissue using RIA, whereas dynorphin B could not be detected. In addition to the endogenous opioids identified, delta-opioid receptors on nerve fibers were also detected by IHC. Binding assays to characterize the opioid binding sites showed that they were specific and saturable for [3H]-naloxone (Kd 7.01 +/- 0.98 nM; Bmax 23.52 +/- 2.23 fmol/mg protein). Our study demonstrates the occurrence of an opioid system in rat achilles tendon, which may be assumed to be present also in other connective tissues of the locomotor apparatus. This system may prove to be a useful target for pharmacological therapy in painful and inflammatory conditions by new drugs acting selectively in the periphery.

Achilles Tendon↗
PubMed2001

Bone reinnervation after fracture: a study in the rat.

Reinnervation after tibial fracture in the rat was studied by analyzing the occurrence of growth-associated protein 43 (GAP-43), a marker for regenerating nerve fibers, and protein gene product 9.5 (PGP-9.5), a marker for mature nerve fibers, by immunohistochemistry. At 3 days postfracture, GAP-43--immunoreactive nerve fibers were first observed in the fracture hematoma and periosteum. At 7 days postfracture, abundant sprouting of GAP-43--positive fibers was seen in the callus, hyperplastic periosteum, and edge of fibrocartilage. In the latter region, the nerve fibers were nonvascular, showing dense ramifications and terminal sprouting close to chondroid cells. At 14 days and 21 days postfracture, many GAP-43--positive fibers were still sprouting into the fibrocartilage and new woven bone. Fine varicose GAP-43--positive fibers also were present in the bone marrow. In contrast to GAP-43, PGP-9.5-positive nerve fibers were observed only occasionally at 3 days postfracture but gradually increased in number from day 14 to 21. Our study shows that intense nerve regeneration occurs in early fracture healing partly unrelated to neovascularization. Considering that neuronal mediators have been shown to participate in local bone formation and resorption, the nerve regeneration observed may prove to be essential for delivery of neuronal mediators required for normal callus formation and/or neovascularization.

Animals↗
PubMed1998

Specific and sensitive detection of the EWS/FLI1 fusion protein in Ewing's sarcoma by Western blotting.

We applied Western blotting, using an antibody against the carboxy terminal of the FLI1 protein, for detection of the 68-kDa EWS/FLI1 fusion protein in cultured Ewing's sarcoma cells and in four surgical biopsies of Ewing's sarcoma. Of six different human cell lines, the 68-kDa fusion protein was identified only in Ewing's sarcoma cells carrying the t(11;22)(q24;q12) translocation. The four samples from Ewing's sarcoma patients were also found to contain the 68-kDa fusion protein. The lowest detection level for total protein loaded on the gel was 0.3 microg. When whole Ewing's sarcoma cells were used for Western blotting without prior protein extraction, the lowest detection level was 1,300 cells. It will be possible to use Western blotting for detection of the EWS/FLI1 fusion protein in the diagnosis of Ewing's sarcoma in surgical biopsy specimens, and possibly also in fine-needle aspirates. As the method is not dependent on the quality of mRNA in the sample and involves no risk of contamination, it will be a powerful complement to the reverse-transcription polymerase chain reaction (RT-PCR).

Blotting, Western↗
PubMed1998

Nonrandom pattern of telomeric associations in atypical lipomatous tumors with ring and giant marker chromosomes.

Atypical lipomatous tumors (ALTs) are cytogenetically characterized by supernumerary ring and giant marker chromosomes. Another common finding in ALT is that the tumor cells are cytogenetically heterogeneous with a variety of mostly nonclonal numerical and structural chromosome aberrations, including telomeric associations. In a series of 48 cytogenetically investigated ALTs, all chromosomal aberrations, clonal as well as nonclonal, were registered. Clonal ring chromosomes were present in 47 cases and giant markers in 11 cases. In 7 cases, 12 clonal telomeric associations were found and 37 cases showed nonclonal associations involving 344 identified telomeres. The telomere associations were nonrandomly distributed, with the telomeres of 11p, 20p, 20q, 9q, 15p, 19q, and 22q being most frequently (8.7-4.1% of all associations) involved; only Xp and Xq were never affected. The pattern of telomeric associations in ALT was compared with literature data on 47 giant cell tumors (880 telomeres), previously reported to show a nonrandom distribution of associations, and 36 sporadic cases of a variety of other human neoplasms (583 telomeres). The analysis indicated that the telomeres of 11p, 19q, and 20q are preferentially involved in associations in several tumor types. Among other structural aberrations in the ALT series, 221 nonclonal and 52 clonal breakpoints were identified, as well as 342 nonclonal and 14 clonal numerical aberrations. The combined data suggest that telomeric associations may predispose to acquired chromosome aberrations in neoplasia.

Adult↗
PubMed1998

Sensory nerves in the interface membrane of aseptic loose hip prostheses.

We studied the presence of sensory nerves by immunohistochemistry in the interface membranes of hip prostheses after aseptic loosening. Substance P (SP), neurokinin A (NKA) and calcitonin gene-related peptide (CGRP) were analysed as was protein gene product (PGP) 9.5, a general marker for nerve fibres. We identified nerve fibres in all samples but differences in their density were found. SP- and NKA-positive fibres were predominantly non-vascular, forming varicose nerve terminals. CGRP-immunoreactive nerve fibres with varicose terminals were seen mostly close to blood vessels, but also as free nerve endings. Sensory neuropeptides participate not only in nociception but also stimulate immune cells to release cytokines. The presence of sensory nerves in the interface membrane may reflect a pathophysiological response contributing to the aseptic loosening of hip prostheses.

Aged↗
PubMed1997

Expression of corticotropin-releasing factor in the peripheral nervous system of the rat.

The occurrence and distribution of corticotropin-releasing factor (CRF) in the rat peripheral nervous system was studied by immunohistochemistry. CRF-positive nerve fibers were identified in the spleen, thymus, synovial membrane of the knee joint and adrenal gland. In general, CRF-positive fibers were seen predominantly in and around the blood vessels; however, many non-vascular thin varicose fibers were also observed. The neuronal character of the immunoreactive fibers was confirmed by staining consecutive tissue sections with a general neuronal marker, protein gene product 9.5. The finding of CRF-positive nerve fibers in the periphery demonstrates a strong anatomical link between the nervous, endocrine and immune systems, and may have pathophysiological implications in the inflammatory and stress-related disorders.

Animals↗
PubMed1996

The development of autonomic innervation in bone and joints of the rat.

The development of autonomic nerves in the hindlimb skeleton, was studied in rats from gestational day (G) 15 to postnatal day (P) 24 by immunoreactivity to neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP). Control labelling with antisera to neurofilaments, protein gene-product 9.5 (PGP 9.5), and nerve terminals, synaptophysin (SYN), showed nerve fibres at G15 and nerve terminals at G19 in the perichondrial tissue. From P4, nerve fibres and terminals were observed within the bone organ. Noradrenergic sympathetic nerves, containing NPY, were first discerned at birth, G21, in the perichondrial tissue and within the bone organ at P4. Autonomic cholinergic nerve fibres, indicated by immunoreactivity to VIP, exhibited a similar temporal and regional occurrence. The diaphyseal parts were first supplied with autonomic nerves at P4. The nerve fibres extended into the metaphyses at P6-8 and finally into the epiphyses at P10, concomitant with the first signs of mineralization. Vascular as well as non-vascular nerve fibres were seen. The study shows that developing bone organ is supplied with autonomic nerves from birth, and the the growth of nerves parallels the mineralisation process. Previous studies have demonstrated that NPY potently inhibits parathyroid hormone (PTH) induced effects on osteoblastic bone cells and that VIP is a strong inductor of bone resorption. NPY and VIP also exert vasoregulatory effects. The combined findings suggest an autonomic influence on bone development.

Animals↗
PubMed1996

19p+ marker chromosome correlates with relapse in malignant fibrous histiocytoma.

In this study, we examined the relationship of 19p13 aberrations, usually leading to addition of unknown material (19p+), and ring chromosomes to clinical outcome in patients with malignant fibrous histiocytoma (MFH). Analysis of 69 MFHs revealed 19 tumors with 19p+ and 24 tumors with ring chromosomes. After a median follow-up period of 36 months, 24 patients developed metastases, and 27 patients developed local recurrences. Ten patients had both local recurrences and metastases. Local recurrence was more common in association with 19p+ than without. Metastasis was more common with 19p+ tumors in high-risk patients (tumor size > 5 cm and grade III-IV; n = 48) than those without 19p+. There was a trend suggesting fewer relapses after tumors with ring chromosomes. 19p+ may be an independent marker of unfavorable outcome in MFH.

Adult↗
PubMed1996

Chromosome rearrangements in synovial chondromatous lesions.

Short-term cultures from one synovial chondroma and three cases of synovial chondromatosis, a lesion for which no previous karyotypic information exists, were cytogenetically analysed. Whereas the chondroma displayed the relatively simple karyotype 46,XY,add(12)(q13),der(17)t(12;17)(q13;q21), more complex changes were found in the three cases of chondromatosis: case 1, 47,XY,der(1)inv(1)(p13q25)del (1)(q25q32), t(1;12)(q25;q13), + 5,der(12)add(12)(p11)t(1;12)(p22;q13); case 2, 47,XY,add(10)(q26), + 20/46 idem,-6/46,XY,t(2;4)(q33;q21), add(21)(p11); and case 3, 44,XY,add(1)(p36), del(1)(p13p22),add(6)(p25), del(7) (q22q32),del(10)(q21),add(11)(q13),-17,-18. The cytogenetic findings strongly suggest that synovial chondro-matosis is a clonal proliferation. Apart from a near-diploid chromosome number, the only recurrent cytogenetic features among the four cases were loss of band 10q26 and rearrangements of 1p13 and 12q13, found in two cases each. While chromosome bands 1p13 and 10q26 have not been reported to be involved in other types of benign chondromatous lesions, the 12q13-15 segment is recurrently rearranged in a variety of chondromatous tumours, e.g. pulmonary chondroid hamartomas. The present finding of translocations affecting band 12q13 in two of the cases emphasises that, irrespective of the anatomical localisation of the tumours, rearrangements of genes in 12q13-15 are important in the development of a large subset of benign and malignant cartilage-forming tumours.

Aged↗
PubMed1996

Cytological diagnosis of bone tumours.

We evaluated the diagnostic accuracy of fine-needle aspiration biopsy in a prospective study of 300 patients with previously undiagnosed bone lesions. Patients with suspected local recurrence of a primary bone tumour or a metastatic lesion of a previously diagnosed malignancy were excluded. Fine-needle aspiration biopsy was performed under radiological control as an outpatient procedure. The series was grouped into three major categories: 1) benign bone lesions including infections; 2) primary malignant bone tumours; and 3) metastases including lymphomas and myelomas. We compared the cytological diagnosis with the final diagnosis as assessed by histological examination and/or the clinical and radiological features. Material considered conclusive for cytological diagnosis was obtained from 251 of the 300 patients. Of the 49 failures, there were 24 aspirates with insufficient cellular yield and 25 in which a diagnosis could not be made although the cytological material was adequate in quantity. Most of the inconclusive aspirates (36/49) were obtained from benign bone lesions. The diagnosis was correct in 239 (95%) of the 251 cases providing adequate cytological material. There were eight (3%) falsely benign diagnoses, one (0.3%) falsely malignant, and three cases in which we were unable to differentiate between sarcoma and a metastasis. Chondrosarcoma (2/12) gave the greatest diagnostic difficulty and Ewing's sarcoma the least (0/9). There were no decisive errors of treatment. All falsely benign or malignant diagnoses were questioned, and led to open biopsy since they did not correlate with the clinical and radiological features. Our study suggests that fine-needle aspiration biopsy is a valid option for the diagnosis of bone tumours. It is a simple outpatient procedure which gives sufficient cytological material for the correct diagnosis in 80% of cases. As with histological analysis of material from open biopsy, the cytological assessment must agree with the clinical and radiological findings.

Adolescent↗
PubMed1995

Capsaicin effects on substance P and CGRP in rat adjuvant arthritis.

The effects of capsaicin on the sensory neuropeptides substance P and calcitonin gene-related peptide were analyzed in the ankle joints and dorsal root ganglia (L2-L6) of adult female Lewis rats. The study included 23 normal rats and 23 arthritic rats, all injected subcutaneously with capsaicin (total dose 200 mg/kg bw). Another two groups of animals from a previous study, i.e., 23 normal rats and 23 arthritic rats not given capsaicin served as controls. Adjuvant arthritis was induced by inoculation with heat-killed mycobacteria. The morphological distribution of sensory neuropeptides was assessed by immunohistochemistry and the tissue concentrations were determined by radioimmunoassay. In normal rats, capsaicin significantly reduced the concentrations of substance P and calcitonin gene-related peptide in ankle joints (54 and 36%, respectively) as well as dorsal root ganglia (40 and 54%, respectively). In arthritic rats those pretreated with capsaicin had significantly lower concentrations of substance P and calcitonin gene-related peptide in dorsal root ganglia (19 and 42%, respectively) compared to the arthritic controls. In the ankle joints, however, only the SP concentration was reduced (42%). Notably, this was accompanied by a 40% reduction in inflammatory response as assessed by comparing the ankle joint weights of the experimental groups. In general, there was a good correlation between the neuropeptide concentrations in ipsilateral ankle joints and the corresponding dorsal root ganglia as assessed in individual rats. The present study of adjuvant induced arthritis shows that capsaicin administration reduces the otherwise up-regulated levels of sensory neuropeptides in dorsal root ganglia and ankle joints. However, capsaicin at the dose given can only mitigate, not completely prevent the development of joint inflammation. Nonetheless, the findings suggest that antineuronal therapy targeted against specific neurotransmitters may prove useful in inflammatory joint disease.

Animals↗
PubMed1995

Increased levels of substance P and calcitonin gene-related peptide in rat adjuvant arthritis. A combined immunohistochemical and radioimmunoassay analysis.

OBJECTIVE: To analyze the occurrence of substance P (SP) and calcitonin gene-related peptide (CGRP) in ankle joints and corresponding dorsal root ganglia (L2-L6) of rats with adjuvant arthritis. METHODS: Arthritis was induced by inoculation with heat-killed mycobacteria. The morphologic distribution of SP and CGRP was assessed by immunohistochemical analysis. Tissue concentrations of the neuropeptides were determined by radioimmunoassay. RESULTS: Neuronal CGRP-like immunoreactivity was clearly increased in the synovium and the dorsal root ganglia, whereas the increase in SP-positive structures was less pronounced. The tissue concentrations of SP and CGRP were significantly increased both in ankle joints and in dorsal root ganglia. CONCLUSION: Levels of sensory neuropeptides are increased under conditions of joint inflammation.

Animals↗