New morphological evidence of the ‘fate’ of growth plate hypertrophic chondrocytes in the general context of endochondral ossification

The ‘fate’ of growth plate hypertrophic chondrocytes has been long debated with two opposing theories: cell apoptosis or survival with transformation into osteogenic cells. This study was carried out on the proximal tibial growth plate of rabbits using light microscopy, scanning and transmission electron microscopy. We focused particularly on the orientation of the specimens included in order to define the mineral deposition and the vascular invasion lines and obtain histological and ultrastructural images at the corresponding height of the plate. Chondrocyte morphology transformation through the maturation process (characterized by vesicles and then large cytoplasmic lacunae before condensation, fragmentation and disappearance of the nuclear chromatin) did not correspond to that observed in the ‘in vitro’ apoptosis models. These findings rather suggested the passage of free water from the cartilage matrix into a still live cell (swelling). The level of these changes suggested a close relationship with the mineral deposition line. Furthermore, the study provided evidence that the metaphyseal capillaries could advance inside the columns of stacked hypertrophic chondrocytes (delimited by the intercolumnar septa) without the need for calcified matrix resorption because the thin transverse septa between the stacked chondrocyte (below the mineral deposition line) were not calcified. The zonal distribution of cell types (hypertrophic chondrocytes, osteoblasts, osteoclasts and macrophages) did not reveal osteoclasts or chondroclasts at this level. Morphological and morphometric analysis recorded globular masses of an amorphous, necrotic material in a zone 0–70 μm below the vascular invasion line occasionally surrounded by a membrane (indicated as ‘hypertrophic chondrocyte ghosts’). These masses and the same material not bound by a membrane were surrounded by a large number of macrophages and other blood cell precursors, suggesting this could be the cause of macrophage recall and activation. The most recent hypotheses based on genetic and lineage tracing studies stating that hypertrophic chondrocytes can survive and transform into osteoblasts and osteocytes (trans-differentiation) were not confirmed by the ultrastructural morphology or by the zonal comparative counting and distribution of cell types below the vascular invasion line.     

Autologous platelet gel for tissue regeneration in degenerative disorders of the knee

Background

The refinement of the use of platelet-derived growth factors that has occurred over the last decade has led to a broadening of the fields of use, in particular for new treatments in orthopaedics aimed at improving tissue regeneration.

Materials and methods

Twenty-seven patients, aged between 18 and 81 years, with a diagnosis of degenerative joint disease lasting for more than 1 year were treated. The patients were divided into two groups, one with arthritis of the knee, the other with degenerative cartilage disease of the knee. Both groups were treated with a therapeutic protocol consisting of a cycle of three infiltrations of platelet-rich plasma at weekly intervals.The extemporaneous preparation was made from a sample of about 8 mL of venous whole blood collected into a specific Fibrin Polymer 2 test-tube from RegenLab^® and centrifuged before addition of calcium gluconate.During the initial pre-treatment evaluation, specific questionnaires were administered, the Numerical Rating Scale (NRS) for subjective measurement of pain and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); these assessments were repeated 7 days after the end of the treatment and at 6 months during the follow-up.

Results

The parameters evaluated improved in both groups after treatment and there was a further improvement after 6 months of follow-up; furthermore, there was a substantial decrease in pain right after the first infiltration.

Discussion

The patients were treated on an out-patient basis by a specifically created multidisciplinary team comprising a transfusion specialist, an orthopaedist and a radiologist, who collaborate in a symbiotic manner. The out-patient protocol exploits the regenerative properties of platelet-rich plasma, which is a low cost treatment; in practice, a diagnostic-therapeutic programme of lower intensity, but of high technical and professional quality is created. The strategy also reduces both the number of hospital services and the pharmacological support required, thereby optimising the use of health care resources.     

Comparison of 18F-dopa PET/CT and 123I-MIBG scintigraphy in stage 3 and 4 neuroblastoma: a pilot study

Purpose

¹⁸F-Dopa positron emission tomography (PET)/CT has proved a valuable tool for the assessment of neuroendocrine tumours. So far no data are available on ¹⁸F-dopa utilization in neuroblastoma (NB). Our aim was to evaluate the role of ¹⁸F-dopa PET/CT in NB and compare its diagnostic value with that of ¹²³I-metaiodobenzylguanidine (MIBG) scintigraphy in patients affected by stage 3?C4 NB.

Methods

We prospectively evaluated 28 paired ¹²³I-MIBG and ¹⁸F-dopa PET/CT scans in 19 patients: 4 at the time of the NB diagnosis and 15 when NB relapse was suspected. For both imaging modalities we performed a scan-based and a lesion-based analysis and calculated sensitivity, specificity and accuracy. The standard of reference was based on clinical, imaging and histological data.

Results

NB localizations were confirmed in 17 of 19 patients. ¹⁸F-Dopa PET/CT and ¹²³I-MIBG scintigraphy properly detected disease in 16 (94%) and 11 (65%), respectively. On scan-based analysis, ¹⁸F-dopa PET/CT showed a sensitivity and accuracy of 95 and 96%, respectively, while ¹²³I-MIBG scanning showed a sensitivity and accuracy of 68 and 64%, respectively (p?18F-dopa PET/CT and 88 by MIBG. On lesion-based analysis, ¹⁸F-dopa PET/CT showed a sensitivity and accuracy of 90% whereas ¹²³I-MIBG scintigraphy showed a sensitivity and accuracy of 56 and 57%, respectively (p?Conclusion In our NB population ¹⁸F-dopa PET/CT displayed higher overall accuracy than ¹²³I-MIBG scintigraphy. Consequently, we suggest ¹⁸F-dopa PET/CT as a new opportunity for NB assessment.     

Immunoregulation of allergic contact dermatitis

Allergic contact dermatitis (ACD) to haptens can serve as a valuable paradigm for understanding the physiopathology of T cell mediated immune responses. In sensitized individuals, exposure to the relevant hapten initiates clinical expression of ACD, which depends on the rapid activation of specific T cells. Mechanisms of tissue damage include direct cytotoxicity against keratinocytes, mostly mediated by CD8+ T cells, and T cell release of cytokines, which amplify the inflammatory response by targeting resident skin cells. The expression of ACD is actively regulated by specialized subsets of T lymphocytes with suppressive functions. In particular, T regulatory cells producing high levels of IL-10 suppress ACD by blocking the functions of dendritic cells. In contrast CD4+CD25+ regulatory T cells prevent immunopathological reactions and maintain peripheral tolerance to haptens by acting via a cell-to-cell contact mechanism. Understanding the role of suppressor T cells and the requirements for their in vivo and in vitro expansion are critical steps for the development of specific desensitization protocols in hapten-allergic individuals. This information may also provide the basis for novel interventions in other immune-mediated diseases.     

Larva currens following systemic steroid therapy in a case of strongyloidiasis

The authors report a case of larva currens following systemic steroid administration for acute contact eczema. The patient was found affected with subclinical strongyloidiasis. Strongyloides is not very common in Northern Italy; it is occasionally diagnosed from stool samples from patients complaining of persisting itching.     

Medium- versus high-dose ultraviolet A1 therapy for urticaria pigmentosa: a pilot study

BACKGROUND: There is currently no definitive cure for urticaria pigmentosa (UP). Psoralen plus ultraviolet A therapy is efficacious in alleviating symptoms and reducing cutaneous lesions. OBJECTIVE: The purpose of this study was to assess the effect of ultraviolet A1 (UVA1) in adult patients with UP and to compare the effectiveness of high-dose (130 J/cm(2)/day for 10 days) and medium-dose (60 J/cm(2)/day for 15 days) UVA1 radiation. METHODS: Ten and 12 adult patients with UP were treated with high-dose or medium-dose UVA1, respectively. The number of skin lesions and dermal mast cells, the presence of Darier's sign, the intensity of pruritus, and quality of life measures were evaluated before, at the end of treatment, and 2 and 6 months later. RESULTS: Baseline characteristics were similar among the 2 groups of patients. In the majority of patients, the number of lesions was not significantly reduced. However, the number of mast cells in lesional skin decreased markedly in most patients by the end of treatment, and it remained low for the whole study period. Pruritus and quality of life improved considerably by the end of treatment, and the improvement was maintained during the 6-month follow up. No significant differences were observed between patients receiving high- or medium-dose UVA1. CONCLUSIONS: UVA1 phototherapy ameliorates both objective and subjective symptoms of adult patients with UP and induces long-term remission in most cases. Medium-dose UVA1 appears at least as effective as high-dose UVA1.     

Correcting for selection bias in HIV prevalence estimates: an application of sample selection models using data from population‐based HIV surveys in seven sub‐Saharan African countries

IntroductionPopulation‐based biomarker surveys are the gold standard for estimating HIV prevalence but are susceptible to substantial non‐participation (up to 30%). Analytical missing data methods, including inverse‐probability weighting (IPW) and multiple imputation (MI), are biased when data are missing‐not‐at‐random, for example when people living with HIV more frequently decline participation. Heckman‐type selection models can, under certain assumptions, recover unbiased prevalence estimates in such scenarios.MethodsWe pooled data from 142,706 participants aged 15–49 years from nationally representative cross‐sectional Population‐based HIV Impact Assessments in seven countries in sub‐Saharan Africa, conducted between 2015 and 2018 in Tanzania, Uganda, Malawi, Zambia, Zimbabwe, Lesotho and Eswatini. We compared sex‐stratified HIV prevalence estimates from unadjusted, IPW, MI and selection models, controlling for household and individual‐level predictors of non‐participation, and assessed the sensitivity of selection models to the copula function specifying the correlation between study participation and HIV status.ResultsIn total, 84.1% of participants provided a blood sample to determine HIV serostatus (range: 76% in Malawi to 95% in Uganda). HIV prevalence estimates from selection models diverged from IPW and MI models by up to 5% in Lesotho, without substantial precision loss. In Tanzania, the IPW model yielded lower HIV prevalence estimates among males than the best‐fitting copula selection model (3.8% vs. 7.9%).ConclusionsWe demonstrate how HIV prevalence estimates from selection models can differ from those obtained under missing‐at‐random assumptions. Further benefits include exploration of plausible relationships between participation and outcome. While selection models require additional assumptions and careful specification, they are an important tool for triangulating prevalence estimates in surveys with substantial missing data due to non‐participation.     

Autonomic modulations of heart rate variability and performances in short-distance elite swimmers

Purpose

Endurance exercise is associated with high cardiac vagal tone, but how the cardiac autonomic control correlates with shorter anaerobic performances is unknown. Therefore, the aim of this study was to evaluate how autonomic modulations of heart rate (HR) variability (V) correlate with performances of short- (<1 min) and very short (<30 s) duration in elite athletes.

Method

Thirteen male swimmers, national-level crawl specialists in short (100-m) and very short (50-m) distances, were enrolled. HR was recorded during 15-min supine rest: (1) in the morning after wake up, (2) in the afternoon before sprint-oriented training sessions, (3) few minutes after training (first recovery phase after swimming cooldown). Heart rate variability (HRV) vagal and sympatho/vagal indices were calculated in time, frequency and complexity domains. Correlations of best seasonal times on 100- or 50-m distances with HRV indices and the velocity at blood lactate accumulation onset (V _OBLA) were calculated.

Results and conclusion

Vagal indices were highest in the morning where they positively correlated with very short-distance times (higher the index, worse is the 50-m performance). Sympatho/vagal indices were highest after training where they negatively correlated with short-distance times (higher the index, better is the 100-m performance). V _OBLA did not correlate with the performances. Therefore, autonomic HRV indices and not V _OBLA predict short and very short, most anaerobic, performances. Results also suggest that a strong cardiac vagal control has no effect on short performances and is even detrimental to very short performances, and that the capacity to powerfully increase the sympathetic tone during exercise may improve short, but not very short performances.