Highly cross-linked versus conventional polyethylene inserts in total hip arthroplasty,a five-year Roentgen stereophotogrammetric analysis randomised controlled trial

BACKGROUND Polyethylene(PE) particles produced by wear of the acetabular insert are thought to cause osteolysis and thereby aseptic loosening of the implant in total hip arthroplasty(THA). As highly cross-linked polyethylene(HXLPE) is presumed to give lower wear rates, in vivo studies are needed to confirm this.AIM To compare the wear of REXPOL, a HXPLE, with conventional PE within the first five years after implantation using Roentgen stereophotogrammetric analysis(RSA).METHODS Patients were randomised to receive either a HXLPE(REXPOL) or a conventional PE insert during primary THA. RSA images were obtained directly postoperative and after 6 wk, 12 wk, 6 mo, 12 mo, 24 mo and five years. Functional outcomes were assessed using the Hip Injury and Osteoarthritis Outcome Score and Harris Hip Score at baseline and five years after surgery.RESULTS The HXLPE(REXPOL) showed less wear in the latero-medial direction. Significant wear rates of conventional PE were seen in the latero-medial and center-proximal direction and in volume and corrected volume, whereas the REXPOL did not show these outcomes over time. Improvement from baseline in functional outcome did not significantly differ.CONCLUSION Total 3 D wear is less in THAs inserted with a REXPOL inlay than a conventional PE inlay after five years. This study confirms, for the first, that the REXPOL HXLPE inlay is preferred to standard PE.     

"Stem cell" origin of the hematopoietic defect in dyskeratosis congenita

We have used the long-term bone marrow culture (LTBMC) system to analyze hematopoiesis in three patients with dyskeratosis congenita (DC), two of whom had aplastic anemia, and the third had a normal blood count (apart from mild macrocytosis) and normal BM cellularity. Hematopoiesis was severely defective in all three patients, as measured by a low incidence of colony-forming cells and a low level of hematopoiesis in LTBMC. The function of the marrow stroma was normal in its ability to support the growth of hematopoietic progenitors from normal marrows seeded onto them in all three cases, but the generation of hematopoietic progenitors from patients marrow cells inoculated onto normal stromas was reduced, thus suggesting the defect to be of stem cell origin. The parents and unaffected brother of one of the families have also been studied in LTBMC and all showed normal hematopoietic and stromal cell function. From this study we speculate that there are some similarities between DC and the defect in the W/Wv mouse.     

CALLA-positive myeloma: an aggressive subtype with poor survival

Detailed immunotyping was carried out on 21 direct myeloma bone marrow aspirates and eight human myeloma cell lines. Four previously untreated common acute lymphoblastic leukemia antigen (CALLA)-positive myeloma patients were identified and six of eight cell lines (75%) were also positive. CALLA positivity, as part of an immature B phenotype, was found to correlate with very aggressive clinical disease: median survival six months v 56 months for the CALLA-negative group.     

[11C]5-HTP and microPET are not suitable for pharmacodynamic studies in the rodent brain

The PET tracer [¹¹C]5-hydroxytryptophan ([¹¹C]5-HTP), which is converted to [¹¹C]5-hydroxytryptamine ([¹¹C]5-HT) by aromatic amino acid decarboxylase (AADC), is thought to measure 5-HT synthesis rates. But can we measure these synthesis rates by kinetic modeling of [¹¹C]5-HTP in rat? Male rats were scanned with [¹¹C]5-HTP (60 minutes) after different treatments. Scans included arterial blood sampling and metabolite analysis. 5-HT synthesis rates were calculated by a two-tissue compartment model (2TCM) with irreversible tracer trapping or Patlak analysis. Carbidopa (inhibitor peripheral AADC) dose-dependently increased [¹¹C]5-HTP brain uptake, but did not influence 2TCM parameters. Therefore, 10 mg/kg carbidopa was applied in all subsequent study groups. These groups included treatment with NSD 1015 (general AADC inhibitor) or p-chlorophenylalanine (PCPA, inhibitor of tryptophan hydroxylase, TPH). In addition, the effect of a low-tryptophan (Trp) diet was investigated. NSD 1015 or Trp depletion did not affect any model parameters, but PCPA reduced [¹¹C]5-HTP uptake, and the k₃. This was unexpected as NSD 1015 directly inhibits the enzyme converting [¹¹C]5-HTP to [¹¹C]5-HT, suggesting that trapping of radioactivity does not distinguish between parent tracer and its metabolites. As different results have been acquired in monkeys and humans, [¹¹C]5-HTP-PET may be suitable for measuring 5-HT synthesis in primates, but not in rodents.     

Recurrent chest pain as the presenting manifestation of spinal meningioma

We report the case of a 9-year-old boy with a spinal cord meningioma whose only manifestations were recurrent episodes of chest pain lasting for 2 years. This case shows that spinal cord meningioma should be considered among the possible causative factors of chronic chest pain in childhood. Chest pain, meningioma, spinal tumors     

Clinical evaluation of biomarkers in Gaucher disease

Novel or candidate biomarkers require thorough evaluation to establish their utility in a clinical setting. This paper describes an evaluation of several established enzyme markers of Gaucher disease and a newly-described chemokine, pulmonary and activation-regulated chemokine (PARC). The ability of the biomarkers to rank patients with Gaucher disease in order of disease severity and organ bulk, and to reflect changes in key clinical parameters in response to enzyme replacement therapy were evaluated. PARC concentrations were found to be reliably correlated with visceral disease and with key clinical responses to enzyme replacement in an unbiased manner. Unlike chitotriosidase and serum angiotensin-converting enzyme activity, genetic variation in serum PARC did not appear to influence its utility as a biomarker.
Conclusion: For each new candidate biomarker of lysosomal storage diseases, a similar clinical evaluation will be required, though the approach will need to be modified according to the clinical features and natural history of each disorder.     

Child Behaviour Checklist classification of behaviour disorder

Objective : The aim of this study was to determine the applicability of the published clinical cut-off scores of the Child Behaviour Checklist (CBCL) for the classification of behaviour disorders.
Methodology : Child Behaviour Checklists were obtained for 1342 subjects newly referred to the six major mental health centres in Melbourne. The normative community sample of 1002 7-, 12- and 15-year-olds was drawn from a school-based asthma prevalence study.
Results : The mean total problem T-score for the children referred to mental health centres was 67 and was above the clinical range for all age groups. Using referral to psychiatric services as the gold standard, the sensitivity and specificity of the CBCL using a cut-off of ≥ 60, was 77.4 and 83.2%, respectively. This compares favourably with the sensitivity of 68% and specificity of 82% for the American sample. Using a cut-off score of ≥ 63, the sensitivity was 70.5% and the specificity was 88.6%. The referred and community samples differed with respect to socio-economic status, family structure and mothers' level of education. Fifty-two per cent of the clinically referred children lived with both parents, compared with 89% of the community sample.
Conclusions : While there are some limitations to this study in terms of both the clinic and community sample, support is provided for the usefulness and applicability of the recommended CBCL cut-off scores in an Australian population.     

Roxatidine versus ranitidine in the treatment of duodenal ulcers: A randomized double-blind controlled multicentre study in Singapore

Roxatidine acetate, a new H₂ receptor antagonist, was compared with ranitidine in the treatment of duodenal ulcers in a double-blind multicentre study. Eighty-four patients with endoscopically proven duodenal ulcer were randomized to receive 150 mg roxatidine acetate or 300 mg ranitidine at bedtime. Repeat endoscopy was performed after 4 weeks (25–33 days) and if the ulcer had not healed, another endoscopy was performed after a further 4 weeks of treatment. Using per protocol analysis 73.6% of ulcers treated with roxatidine healed at 4 weeks compared to 72.2% of ulcers treated with ranitidine (P=NS). The healing rates at 8 weeks were 92% with roxatidine and 83.3% with ranitidine (P=NS). Using equivalence tests, the healing rate of roxatidine was found to be equivalent to that of ranitidine within a 20% region. Roxatidine users took significantly less antacids than ranitidine users (P < 0.05). There were no significant adverse effects due to roxatidine or ranitidine. Roxatidine is a safe effective drug in the treatment of duodenal ulcers with a healing rate comparable to that of ranitidine.     

Ultrasonic features of pyogenic liver abscesses

Ultrasonic features of 21 surgically confirmed pyogenic liver abscesses in 18 patients were analyzed. Typical lesions were round or ovoid with a discrete, irregular, echo-poor margin. The number and intensity of internal echoes and sound transmission were variable. Such lesions can be aspirated percutaneously for definitive preoperative diagnosis. Pyogenic liver abscesses appear to have more ragged walls and are less frequently elliptical or multilocular than abscesses elsewhere in the abdomen.