Total ankle arthroplasty: optimizing computed tomography imaging protocol

Objective

To evaluate parameters and positioning when imaging total ankle prostheses on computed tomography (CT).

Materials and methods

An ankle prosthesis implanted into a pig’s knee joint underwent 16 different CT imaging protocols. Four defects were drilled around prosthesis components simulating periprosthetic osteolytic lesions. The specimen with the implant was imaged in four different orientations with the tibial stem parallel to the table and at 25, 45, and 90° angles to it. The protocol consisted of scanning at 100, 120, and 140 kVp in every position with a pitch of 1.2. The scanning at 120 kVp in every position was repeated with a pitch of 1.0.

Results

CT proved to be a reliable imaging modality when studying periprosthetic lesions adjacent to the ankle prosthesis when the tibial stem alignment was parallel to the table. When imaging at higher angles, metal artifacts distorted the image, making the analysis of periprosthetic bone structure unreliable. There were no statistically significant differences between different tube voltages or pitch in volume measurements of the osteolytic lesions.

Conclusions

CT is a reliable imaging method to evaluate periprosthetic bone structure around ankle prostheses when orientation of the prosthesis and acquisition parameters is optimized.     

A trypsin-like protease from Bacteroides gingivalis: partial purification and characterization

Extracts of cell sonicates of Bacteroides gingivalis were shown to contain proteo-lytic enzymes capable of degrading connective tissue proteins. In this study, neutral proteolytic enzymes, i.e. collagenase and a trypsin-like protease, were isolated. The trypsin-like protease was readily separated from collagenase by affinity chromatography on Benzamidine-Sepharose. Proteases were further purified by gel filtration on Sephacryl S-200; apparent molecular weights of 35 kDa and 70 kDa were obtained for a trypsin-like protease and collagenase, respectively. Further characterization of the potent trypsin-like protease showed that the enzyme was inhibited by serine protease inhibitors phenylmethylsulfonyl fluoride and benzamidine and by metalloprotease inhibitor EDTA, as well as ascorbic acid. Activation of the enzyme was observed with reducing agents and human serum. The trypsin-like protease was found to be capable of degrading native type IV collagen and denatured type I collagen but not native type I collagen. Thus, we conclude that in addition to collagenase a potent trypsin-like protease from Bacteroides gingivalis may be involved in the etiopathogenesis of periodontal disease. Since the trypsin-like protease is able to degrade the basement membrane collagen (type IV) in the presence of human serum, this enzyme may be a potent virulence factor of Bacteroides gingivalis in relation to invasiveness and connective tissue destruction.     

The association between visual acuity and functional limitations: findings from a nationally representative population survey

PURPOSE: To determine the independent effect of visual acuity on individual activities of daily living (ADL), instrumental activities of daily living (IADL) and mobility. METHODS: Cross-sectional survey on a sample representing the Finnish population aged 55 years and above. Of the 3392 eligible people, 3185 (93.9%) were interviewed, 2870 (84.6%) attended a comprehensive health examination, and 2781 (82.0%) had distance visual acuity (VA) assessed. A home interview included assessment of ADL, IADL and mobility, demographic variables and chronic conditions. Mobility measurements and binocular VA were assessed during the examination. RESULTS: Prevalence of ADL, IADL, and mobility limitations increased with decreasing VA (p<0.001). Visually impaired persons (VA< or =0.25) had ADL disabilities four times more likely than those with good VA (VA> or =0.8) after adjustment for socio-demographic and behavioral factors, and chronic conditions (OR 4.36, 95%CI 2.44-7.78). Limitations in IADL and measured mobility were five times as likely (OR 4.82, 95%CI 2.38-9.76 and OR 5.37, 95%CI 2.44-7.78, respectively), and self-reported mobility limitations were three times as likely (OR 3.07, 95%CI 1.67-9.63) as in persons with good VA. CONCLUSIONS: Decreased VA is strongly associated with functional limitations, and even a slight decrease in VA was found to be associated with limitations in functioning.     

Association of SLC11A1 (NRAMP1) with persistent oligoarticular and polyarticular rheumatoid factor–negative juvenile idiopathic arthritis in Finnish patients: Haplotype analysis in Finnish families

Objective

The SLC11A1 (formerly called NRAMP1) gene is important in natural resistance to a variety of intracellular infections mediated by macrophages and has been proposed as a candidate gene for autoimmune disease susceptibility. The aim of this study was to examine susceptibility in Finnish patients with persistent oligoarticular and polyarticular rheumatoid factor (RF)–negative juvenile idiopathic arthritis (JIA) due to the presence of the SLC11A1 locus on chromosome 2.

Methods

A total of 234 Finnish JIA nuclear families and 639 elderly Finnish controls without a history of JIA were evaluated for association with JIA at 3 intragenic single‐nucleotide polymorphisms: an intragenic insertion/deletion, a promoter microsatellite (NRAMP1), and a 3′ microsatellite (D2S1471).

Results

Analysis of marker haplotypes demonstrated a strong association of Finnish JIA with 6‐marker, 4‐marker, and 2‐marker haplotypes. Most impressively, 1 of the 6‐marker haplotypes showed an odds ratio (OR) of 4.0 (95% confidence interval [95% CI] 2.6–6.2) in all JIA patients, 3.5 (95% CI 1.9–6.5) in those with persistent oligoarticular JIA, and 4.1 (95% CI 2.5–6.7) in those with polyarticular RF‐negative JIA. Stratification of the haplotype data suggested that susceptibility to JIA in the haplotype spanning the SLC11A1 locus is independent (P < 0.01) of an association with a DRB1 JIA shared epitope (DRB1*JIASE) that includes well‐characterized strong susceptibility to DRB1*08 and *11 alleles. This SLC11A1 haplotype also had an additive effect with DRB1*JIASE in those with polyarticular, but not those with persistent oligoarticular, disease (P = 0.06, OR 2.9 [95% CI 0.9–9.2] versus P = 0.5, OR 1.6 [95% CI 0.4–6.0]).

Conclusion

Taken together, these data provide support for the existence of a locus at or near SLC11A1 that is a strong susceptibility factor for JIA in Finnish patients.

     

Multi-score estimation of catecholamine fluorescence for clinical purposes

Experience accumulated at multi-score semiquantitation of catecholamine fluorescence of glyoxylic acid-treated stretch preparations of human clinical specimens is presented. The methodology and criteria of quantitation are described in detail. For an example, comparison between 3 different methods for analyzing neural-bound noradrenaline in human myocardial tissue in various heart diseases (obtained during the course of cardiac surgery) is presented: Biochemical determination of tissue noradrenaline content multi-score estimation of catecholamine fluorescence of glyoxylic acid-treated stretch preparations microfluorimetric analysis of the same stretch preparations. The results show that the multi-score estimation method gives a reliable concept of the relative amounts of noradrenaline stored in the intrinsic adrenergic nerve net (corresponding closely to the individual and group differences observed at biochemical noradrenaline determination). In addition, possible regional differences, alterations in the structural integrity of the inbuilt intrinsic nerve net, and other structural changes (e.g. pathological catecholamine accumulations) are easily recognized, whereas biochemical estimation cannot give information on structural aspects, which may have important clinical repercussions. Microfluorimetry does not seem suitable for studies on human myocardial specimens for several reasons which are discussed. The method of multi-score estimation of catecholamine fluorescence described and discussed is recommended for other similar and related studies on human clinical materials.     

Epileptic seizures in aspartylglucosaminuria: a common disorder

Aspartylglucosaminuria (AGU) is a lysosomal storage disorder with reduced life-span. An analysis of 121 Finnish patients showed that 22 to 78 adults (28%) and one of 43 children (2%) had epileptic seizures. Twelve patients had the onset of attacks after the age of 30 years. Eleven patients had generalized, nine partial and three unclassified seizures. The response to carbamazepine was good. The major interictal EEG abnormality was the attenuation of the amplitude found in 10/27 patients. The brain CT-scans showed diffuse atrophy in 8/11 patients.