Nationwide collaborative study of HLA class II associations with distinct types of juvenile chronic arthritis (JCA) in Greece

The aim of this study was to investigate the association of different groups and subgroups of juvenile chronic arthritis (JCA) with HLA class II (DR, DP, DQ) alleles and/or haplotypes. Groups and subgroups were mainly distinguished on the basis of the type of onset, the course and complications of the disease, and some predefined disease markers according to the criteria proposed by the ILAR Standing Committee (Chile, 1994). On the basis of these criteria the following five JCA groups and their subgroups were included in the study: (1) definite systemic onset (n = 25) and systemic progressing to persistent arthritis (n = 14); (2) JCA of oligoarthritis onset (O-JCA, n = 124) and of oligoarthritis onset and course (n = 98), O-JCA of early (< 6 years) or late (> 6 years) onset (EOO-JCA n = 71 and LOO-JCA n = 44), O-JCA with ANA positive (n = 69) or negative (n = 55) and O-JCA progressing to extended arthritis (n = 22); (3) JCA of polyarthritis onset (P-JCA) with rheumatic factor (RF) negative (n = 29), and P-JCA RF negative with antinuclear antibodies (ANA) positive (n = 13) or negative (n = 16); (4) JCA complicated with chronic anterior uveitis (CAU, n = 32); (5) juvenile psoriatic arthritis (n = 20). To assess the HLA allele frequencies in the above 223 Greek children with JCA, these frequencies were compared to those of 98 age-matched and 250 adult controls. The main findings were the following. A common HLA-DRB1* allele was not involved in the JCA groups and subgroups studied; on the other hand, the DQA1*0501 allele was found to be associated with different JCA groups/subgroups (O-JCA, P-JCA RF-negative ANA-positive, JCA with CAU), probably suggesting a closer relationship of this locus with the immunogenetic background of JCA. The DPB1*0201 allele was associated with the development of either EOO-JCA or CAU. Susceptibility to CAU was stronger when the DPB1*0201 was combined with the presence of DRB1*13. Another allele, DQB1*0301, was also associated with O-JCA and CAU. Finally, no specific HLA class II allele was found to be related to the presence of ANA or psoriatic lesions or to the severity of the arthritis. Our findings suggest that the wide clinical and laboratory spectrum of JCA is associated with an immunogenetic background that is linked with HLA alleles of more than one locus. Some of them, such as the DPB1*0201 allele, confer susceptibility to certain clinical onsets and courses or complications of the disease. The rapidly advancing techniques of typing of DNA profiles may lead to more definite conclusions.     

Inferior subluxation of the fibular head following tibial lengthening with a unilateral external fixator

BACKGROUND: Inferior subluxation of the proximal part of the fibula has been reported to occur with distraction osteogenesis of the tibia; however, the clinical sequelae of this subluxation are unknown. The purpose of this study was to evaluate inferior subluxation of the proximal part of the fibula and its possible clinical implications in patients who had undergone tibial lengthening by distraction osteogenesis with use of a unilateral external fixator. METHODS: Thirty tibiae in seventeen patients with a variety of conditions underwent tibial lengthening by distraction osteogenesis with use of a unilateral external fixator and were followed clinically and radiographically for a mean of two years and ten months (range, two to four years). Ten patients were female and seven were male. Their mean age at the time of the surgery was seventeen years (range, eight to twenty-five years). The mean tibial lengthening was 8.1 cm (range, 3.5 to 13 cm). RESULTS: An inferior shift of the fibular head in relation to the tibia was evident in all cases. The shift, which ranged from 0.4 to 3.3 cm, was proportionally related to the amount of tibial lengthening. This type of subluxation is probably attributable to the tension that is exerted by the intact interosseous membrane during the distraction as well as to the tension of the regenerated bone of the fibula and the fact that the fibula itself is not fixed or directly lengthened by the external fixator. CONCLUSIONS: It appears that inferior subluxation of the fibula is a common phenomenon in patients undergoing tibial lengthening by distraction osteogenesis with use of a unilateral external fixator. However, no clinical symptoms or findings related to the inferior subluxation of the fibula were found in our series.     

Thoracic outlet syndrome: evaluation with CT

Diagnosis of the thoracic outlet syndrome is often difficult, particularly in patients without osseous abnormalities on plain radiographs. The radiographic and computed tomographic (CT) findings were reviewed from 27 patients with thoracic outlet syndrome and 21 normal subjects. The plain radiographs and CT scans were assessed by two independent observers without awareness of the clinical history. Fifteen patients with thoracic outlet syndrome had osseous abnormalities (anomalous cervical ribs; abnormally long, drooping C-7 transverse processes) identifiable on plain radiographs. CT did not provide further diagnostic information in the patients with abnormal radiographs. Eight of 12 patients (66%) with normal plain radiographs had abnormal findings on CT scans, consisting of impingement of the C-7 transverse process on the scalene triangle or anteromedial aspect of the middle scalene muscle. Only two of 21 control patients (9.5%) displayed this CT abnormality (P less than .01). CT may be useful in patients with symptoms suggestive of thoracic outlet syndrome and no osseous abnormalities on plain radiographs.     

Histological characterization of a delayed wound healing model in pig

Chronic wounds, such as venous ulcers and pressure ulcers, frequently remain unresponsive to currently available treatments. Several animal models of wound healing have been published, including models of impaired healing developed to mimic the clinical condition of chronic wounds better. We used a delayed wound healing model in the pig that uses irradiation of the skin prior to creation of the surgical wounds and characterized it histologically. Radiation was used on one side of the back prior to making four full-thickness wounds on each side. Clinical observations were performed to record granulation tissue, reepithelialization, and wound area as a function of time. Histology data were obtained at 1, 2, 3, and 4 weeks, and slides were stained with hematoxylin and eosin for general observations. Immunohistochemistry was performed using laminin as a marker for blood vessels, and the number, size, and circularity of blood vessels found in the granulation tissue were measured. Our results show that this model causes a delay in wound healing that is mostly apparent between days 7 and 15. Granulation tissue took more time to form and fill the wounds on the irradiated side, and blood vessels were slower to develop. Blood vessels were larger and more irregular in shape on the irradiated side than on the control side. After 2 weeks, healing resumed, indicating that the induced damage was not irreversible. These results suggest that this model can be used to test the effects of therapeutic approaches intended to treat chronic wounds.     

Superficial- and deep-tissue temperature increases in anesthetized dogs during exposure to high specific absorption rates in a 1.5-T MR imager

Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.