Richard I. Davis

Improved detection of infection in hip replacements

Our aim was to determine if the detection rate of infection of total hip replacements could be improved by examining the removed prostheses. Immediate transfer of prostheses to an anaerobic atmosphere, followed by mild ultrasonication to dislodge adherent bacteria, resulted in the culture of quantifiable numbers of bacteria, from 26 of the 120 implants examined. The same bacterial species were cultured by routine microbiological techniques from only five corresponding tissue samples. Tissue removed from 18 of the culture-positive implants was suitable for quantitative tissue pathology and inflammatory cells were present in all samples. Furthermore, inflammatory cells were present in 87% of tissue samples taken from patients whose implants were culture-negative. This suggests that these implants may have been infected by bacteria which were not isolated by the techniques of culture used. The increased detection of bacteria from prostheses by culture has improved postoperative antibiotic therapy and should reduce the need for further revision.

Cell proliferation studies in primary synovial chondromatosis

Primary synovial chondromatosis (PSC) is thought to be a cartilaginous metaplasia, but it may recur locally and malignant change has been reported. Histologically, the cartilage is usually cellular, with binucleate forms. These findings suggest that the disease is not simply a metaplasia but imply a proliferative component. In this study, immunohistochemical detection of Ki‐67 protein using an antigen retrieval microwave heating technique and DNA image cytometry (VIDAS image analysis system) has been used to assess the proliferative activity in 20 cases of PSC and the results have been compared with those obtained in other cartilage tissues: ten enchondromas, ten chondrosarcomas, and ten samples of normal articular cartilage. There was no detectable staining for Ki‐67 protein in cases of PSC or in benign tissues, but there was a significant association between Ki‐67 labelling index and grade in the chondrosarcomas (P<0·01). The absence of mitotic figures and the lack of Ki‐67 protein in PSC are consistent with a metaplasia. All enchondromas gave diploid DNA histograms but non‐diploid histograms were obtained in eight cases (40 per cent) of PSC, with significant populations of hyperdiploid and DNA aneuploid cells. The mean DNA content, the percentage of hyperdiploid cells, the percentage of DNA aneuploid cells, and the 2c deviation index were all significantly higher in PSC than in enchondromas (P<0·01). These findings with image cytometry suggest a proliferative process in the development of at least some cases of PSC. In terms of cell proliferative activity, PSC appears to occupy a position which is intermediate between benign enchondromas and malignant chondrosarcomas, which may explain the aggressive clinical behaviour occasionally seen in this condition.

Detection of prosthetic joint biofilm infection using immunological and molecular techniques

Publisher Summary This chapter describes how the detection of bacteria by culture from revision hip prostheses can be improved by employing strict anaerobic techniques and by using mild ultrasonication to dislodge bacteria adhering to the surface of the retrieved implants. Nonculture techniques that can be used to further improve the detection of infection, including examination of the inflammatory response in implant-associated tissue and the detection of bacteria using immunological and polymerase chain reaction (PCR)-based molecular approaches, are also described. The use of strict anaerobic techniques and mild ultrasonication has resulted in bacteria being cultured from 26 of 120 (22%) retrieved implants examined. The use of nonculture techniques to improve the detection of prosthetic joint biofilm infection coupled with appropriate postoperative antibiotic therapy should improve the clinical outcome for patients undergoing revision hip surgery.

Melorheostosis in a family with autosomal dominant osteopoikilosis

We describe a 19-year-old woman with melorheostosis and osteopoikilosis (mixed sclerosing bone dysplasia). Her sister and mother had osteopoikilosis, but no evidence of melorheostosis. Isolated melorheostosis and melorheostosis with osteopoikilosis are sporadic disorders. Osteopoikilosis is an autosomal dominant trait. Mixed sclerosing bone dysplasia in a family with autosomal dominant osteopoikilosis raises the possibility that the two bone disorders may be related. This family and that of Butkus et al. [1997: Am J Med Genet 72:43-46] suggest that the melorheostosis could be due to a second mutation at the same locus as that which causes autosomal dominant osteopoikilosis.

Raman microscopy in the diagnosis and prognosis of surgically resected nonsmall cell lung cancer

The main curative therapy for patients with nonsmall cell lung cancer is surgery. Despite this, the survival rate is only 50%, therefore it is important to more efficiently diagnose and predict prognosis for lung cancer patients. Raman spectroscopy is useful in the diagnosis of malignant and premalignant lesions. The aim of this study is to investigate the ability of Raman microscopy to diagnose lung cancer from surgically resected tissue sections, and predict the prognosis of these patients. Tumor tissue sections from curative resections are mapped by Raman microscopy and the spectra analzsed using multivariate techniques. Spectra from the tumor samples are also compared with their outcome data to define their prognostic significance. Using principal component analysis and random forest classification, Raman microscopy differentiates malignant from normal lung tissue. Principal component analysis of 34 tumor spectra predicts early postoperative cancer recurrence with a sensitivity of 73% and specificity of 74%. Spectral analysis reveals elevated porphyrin levels in the normal samples and more DNA in the tumor samples. Raman microscopy can be a useful technique for the diagnosis and prognosis of lung cancer patients receiving surgery, and for elucidating the biochemical properties of lung tumors.

C-erb B-2 staining in primary synovial chondromatosis: A comparison with other cartilaginous tumours

In this study C‐erb B‐2 immunostaining has been used to highlight distinct differences between the cartilage found in primary synovial chondromatosis (n=20), normal articular cartilage (n=10), benign enchondromas (n=10), and chondrosarcomas (n=10). There was no positive staining in either the normal cartilage or the chondromas, but 15 cases of synovial chondromatosis showed at least some staining, although in the majority of cases fewer than 50 per cent of cells stained positive. There was no correlation between cellularity/pleomorphism and the extent or intensity of staining. Five of the chondrosarcomas were positive, with more than 50 per cent of cells showing positive staining in three of these cases. All positive cases in this series showed a diffuse cytoplasmic staining pattern. Despite these results, there was no Ki‐67 positive staining in synovial chondromatosis, which tends to suggest that the demonstrated expression of C‐erb B‐2 is not related to proliferative activity. The significance of this staining remains undetermined.