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Biomedical subjects

A Aho

Publications and source records attributed to A Aho.

13 recordsLinked to original sources
PubMed2001

Cysteine proteinases in chondrosarcomas.

The aim of the present study was to define the role of cathepsins B, H, K, L and S in the pathogenesis of human chondrosarcomas. For this purpose 40 tumour samples obtained from 12 patients with the diagnosis of conventional chondrosarcoma were systematically investigated for the expression of cathepsin mRNAs by Northern hybridisation, and for immunohistochemical localisation of the proteins. Northern analysis demonstrated the highest levels of cathepsins B and L in a recurring grade 1 chondrosarcoma, and in a grade 3 chondrosarcoma and in fibrous histiocytomas. Increased expression of cathepsin K mRNA was seen in seven chondrosarcomas, as well as in control tumours; fibrous histiocytomas, osteosarcomas, enchondromas and a giant cell tumour of bone. Cathepsin L was immunolocalised within the large chondrocytes, while cathepsin K was predominantly localised in large multinucleated osteoclastic cells and in some hypertrophic chondrocytes. These results suggest that chondrosarcoma can be included in the growing list of tumours, where cathepsins may well be involved in tumour progression. The simultaneous upregulation of cathepsins B and L, together with matrix metalloproteinase-13, and the association of cathepsin K with negative prognostic parameters suggests that an aggressive biological behaviour of chondrosarcoma may be related to the synthesis of cysteine proteinases and activation of other proteolytic enzymes. If this turns out to be the case, cathepsin inhibitors could provide the much needed adjuvant therapy for chondrosarcomas.

Adult↗
PubMed2001

Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in human chondrosarcomas.

The aim of the present study was to characterise the ability of malignant chondrosarcomas to invade normal bone by analysing their production of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). For this purpose 12 chondrosarcomas were investigated for the expression of mRNAs for several MMPs and all 4 TIMPs by Northern hybridisation, and for immunohistochemical localisation of the proteins. A characteristic finding of these analyses was increased expression of MMP-13, MMP-14 and TIMP-2 mRNAs in chondrosarcomas when compared with nonmalignant control samples. Individual chondrosarcomas also exhibited elevated levels of MMP-1, MMP-7 and MMP-9 mRNAs. The results of Northern hybridisations were supported by immunohistochemical stainings of the corresponding tumour areas for MMP-2, MMP-14 and TIMP-2, further suggesting that these may have prognostic value for determining whether individual chondrosarcomas are locally aggressive or have a probability of recurrence. Another finding of the present study was a marked heterogeneity in histologic appearance and gene expression of the chondrosarcomas, emphasising the importance of analysing several areas of these tumours to get representative results. These findings suggest that analysis of MMPs could be a useful diagnostic indicator in patients with cartilaginous tumours and could help in differentiating between a low-grade malignant chondrosarcoma and a benign growing enchondroma.

Adolescent↗
PubMed1999

Immune responses to osteoarticular allografts of the knee--cytokine studies.

Immunological behaviour in correlation with bone allograft survival was studied in peripheral blood and synovial fluid from seven patients who had undergone large bone resection and allograft transplantation of the knee. Plasma and synovial fluid samples for cytokine measurements [interleukin (IL-1beta, IL-6) and tumour necrosis factor alpha (TNF-alpha)] were drawn from peripheral blood for diagnostic arthrocentesis. Two patients were monitored using consecutive sampling up to 12 months postoperatively. Graft survival was considered excellent, but local or diffuse resorption and also fatigue fractures were seen. These findings show that soluble products of T-cell, macrophage and osteoblast origin, produced as a response to the bone-graft antigens, might be responsible for the bone resorption seen in our material. The elevated IL-1beta and TNF-alpha levels detected support this statement.

Adult↗
PubMed1998

Tissue perfusion after intramedullary nailing of tibial shaft fracture.

BACKGROUNDS AND AIMS: To measure noninvasively the effect of circulative changes caused by fracture and intramedullary nailing on tibialis posterior (TPA), dorsalis pedis (DPA) and sum (TPA + DPA) arterial peak signals, transcutaneous oxygen tension (PtcO2) as well as local skin temperature (T) in patients with tibial shaft fractures. PATIENTS, MATERIAL AND METHODS: A total of thirty tibias consisting of ten closed, reamed, intramedullary nailed simple tibial shaft fractures (Type AO A), ten contralateral tibias and as controls, ten intact tibias of healthy volunteers. The measurements took place one day before and immediately after nailing, six hours later and during five days postoperatively. The values were compared to those of contralateral legs and to control legs. RESULTS: In the nailed legs the mean TPA and PtcO2 remained at a significantly lower level compared to the contralateral legs throughout the study (p < 0.003 in both cases). However, the alterations in DPA and TPA + DPA were not statistically significant. Additionally, skin temperature on the fracture site was averagely 3 degrees C warmer than that of the contralaterals (p < 0.001). All the measured parameters were statistically significantly higher in control legs compared to contralateral legs. There were no statistically significant differences between pre- and postoperative values in any measured parameters. CONCLUSION: The changes in the local tissue perfusion variables measured in the present study reflect rather the injury mechanism itself than the effect of reaming and intramedullary nailing in simple tibial fractures. Additionally, arterial circulation was reduced in the contralateral legs.

Adult↗
PubMed1996

Enterostatin in gut endocrine cells--immunocytochemical evidence.

The presence of enterostatin, a pentapeptide acting as a potential satiety signal in rats, was investigated in rat intestine by immunocytochemical methods. Using antibodies directed against the C-terminal part of enterostatin, the peptide was identified in endocrine cells in the antral part of the stomach and in the small intestine of rat. The immunoreactive cells were more frequent in the antrum and duodenum and became gradually fewer towards the distal small intestine. In some of the labeled endocrine cells, a coexistence of enterostatin with serotonin was revealed by immunocytochemical double staining, implying that the cells were enterochromaffin cells. In the pancreas, no enterostatin-immunoreactive cells were detected, indicating enterostatin to be included in its parent molecule, procolipase. In addition, the existence of procolipase in the gastrointestinal tract, including the pancreas, was investigated. Procolipase immunoreactivity was also identified, except in the pancreas, in chief cells in the fundus region of the stomach. The number of labeled cells declined distally in the stomach, finally being absent in the intestine. Immunoreactive enterostatin was measured with a specific ELISA method. Intestinal content and serum were found to average 540 +/- 70 and 50 +/- 4 nM, respectively. Pancreatic duct ligation strongly reduced the levels of enterostatin in intestinal content to 5.4 +/- 1.5 nM (p < 0.001), and also reduced the serum enterostatin level to 35 +/- 5 nM (p < 0.05). It is concluded that the peptide enterostatin in the rat is produced both in the exocrine pancreas, as part of pancreatic procolipase, and in gut endocrine cells, both sources of peptide being important for the circulating enterostatin.

Amino Acid Sequence↗
PubMed1989

F-18 fluorodeoxyglucose: its potential in differentiating between stress fracture and neoplasia.

F-18 fluorodeoxyglucose (FDG) accumulates into regions of enhanced glucose uptake and metabolism such as the brain, heart, and malignant tumors. The clinical usefulness of this positron-emitting radiopharmaceutical is illustrated in a case where the clinical picture and CT indicated a malignant bone lesion in the clavicle. Histologically a stress fracture was found secondary to chronic strain on the clavicle. On follow-up the lesion's course was benign. Planar imaging with F-18 FDG was performed twice during follow-up, and on both occasions there was no accumulation of radioactivity over the suspicious area, indicating normal glucose consumption. This case demonstrates the differential diagnostic potential of F-18 FDG and shows that clinically useful information may be obtained without a position emission tomograph.

Adolescent↗
PubMed1989

Rupture of the urinary bladder, a potentially serious condition.

During the years 1969 to 1983, 61 patients with rupture of the urinary bladder were treated at the Department of Surgery, University of Turku, Finland. The etiology of the injury was accident trauma in 48%, iatrogenic trauma in 28%, minor trauma in association with misuse of alcohol in 21% and other causes in 3% of the cases. In the first three groups the most reliable signs for diagnosing rupture were abdominal pain and tenderness, together with macroscopic or microscopic haematuria. In some cases cystography was of decisive importance in making the diagnosis. The prognosis for this condition, especially when it was associated with other injuries, was serious. Nine patients (14.8%) died and 35 patients (57.3%) had postoperative complications, for the most part infection-related. Fifty-nine patients underwent operative exploration and repair of the bladder, followed by urethral catheter drainage. Two patients were treated conservatively, with an indwelling urinary catheter only.

Adult↗
PubMed1987

A giant unhomogenous leiomyoma simulating ovarian cancer. A case report.

We describe a case of a giant unhomogenous uterine leiomyoma that simulated ovarian cancer both clinically, roentgenologically (computerized tomography) and ultrasonically. As an incidental finding there was also a carcinoma in situ of the endometrium. The difficulties in the differential diagnosis of an abdomino-pelvic mass are discussed, and the significance of laparotomy also as a diagnostic method is emphasized.

Diagnosis, Differential↗
PubMed1987

Nerve fibre counts for an intercostal nerve to cauda equina nerve root anastomosis.

Mean nerve root diameters of thoracal, lumbal and sacral roots have been determined and the corresponding cross section areas calculated. The myelinated axons of these roots have been counted and the axon densities calculated. The myelinated axons of 3 lower intercostal nerves have also been counted. One intercostal nerve has with about 9,000 myelinated fibres enough axons for the regeneration of the ventral (3,000) and dorsal (16,000) myelinated fibres of the sacral roots 3 and 4 together. One intercostal has enough nerve fibres to reconstruct urinary bladder and bowel function on one side. The importance of performing a nerve anastomosis which considers functional aspects has been emphasized.

Aged↗
PubMedDate not supplied

Survival of 25 osteoarticular allografts followed more than 10 years.

An evaluation of the long-term survival rate of 25 osteoarticular allografts was made. Clinical analysis was based on the Mankin scale and the Musculoskeletal Tumor Society (MSTS) Grading system. After a mean follow-up time of 15 years 76% of the osteoarticular allografts had good or excellent rating. The MSTS scale revealed a mean score of 89% for those 20 grafts still functioning according to their primary purpose. Allograft related complications occurred in 32% of the cases being most common among malignant cases. Due to the rather good long-term results, osteoarticular allografts can still be recommended for hemicondylar allograft reconstruction in benign lesions.

Adult↗
PubMedDate not supplied

Microanatomy and number of nerve fibres of the lower intercostal nerves with respect to a nerve anastomosis. Donor nerve analysis. I. (IV).

A human intercostal nerve has about 10,000 myelinated nerve fibres, of which about 1000 to 2000 are motor. At about the axillary line the nervus intercostalis splits into the ramus cutaneous lateralis and a deep branch to the musculus rectus abdominis and other muscles. The ramus cutaneous lateralis consists of 2 skin branches of about 3000 nerve fibres and a muscle branch to the musculus obliquus externus of about 400 to 1100 nerve fibres. The deep branch to the musculus obliquus internus, the musculus transversus and the musculus rectus abdominis and the anterior skin consists of about 2500 to 7000 fibres of which 400 to 1700 are skin fibres. There is indication that the muscle branch to the musculus obliquus externus has about 50% motor fibres. The intercostal nerve is, as it splits after about 20 cm into 4 branches, a suitable donor of at least 2 different muscle functions and a skin sensible function for a direct nerve anastomosis. A crude model for calculating matching probabilities of motor and sensory fibres between donor and acceptor nerves is introduced. Besides the importance of having enough donor nerve fibres, it is calculated that the small amount of motor nerve fibres can be best used if muscle branches of the donor nerves are connected to muscle branches of the acceptor nerves. Because of the separation between normal laboratory animals and humans on the phylogenetic scale, differences in regeneration and plasticity are discussed.

Anastomosis, Surgical↗