Identification of CD8+ T cell PRDM1 in high-risk human plaques and its regulatory role in murine lesion development

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Fritz Thyssen Stiftung

T cells have a prominent role in the pathogenesis of atherosclerosis, although their function in atherosclerotic plaques is only partly understood. In this study, we utilize the advantages of high-throughput techniques and data analytic strategies to compare the inherent biological changes of T cells during plaque transition from a stable, non-haemorrhaged (low-risk) to a rupture-prone, haemorrhaged (high-risk) phenotype.

We classified 43 human carotid arterial lesions into high- and low-risk plaques based on the presence/absence of intraplaque hemorrhages. RNA from these lesions was isolated and microarray gene expression data was obtained and analyzed by Weighted Gene Co-expression Network Analysis. A strong T cell signalling signature was identified in high- versus low-risk plaques, influencing angiogenesis and interferon-related processes. Bayesian network inference, cell type deconvolution and single-cell RNA sequencing analysis revealed that the T cell-associated gene program was linked to effector-memory cytotoxic, CD8+ T cells. This gene program appeared driven by CD8+ T cell-related transcription factors, including RUNX3, IRF7 and most importantly PRDM1. To validate these findings, we demonstrated in a murine model that T cell PRDM1 plays a key role in plaque formation, as atherosclerotic mice with a T cell specific Prdm1 deficiency developed larger and more advanced atherosclerotic plaques compared to control mice.

In conclusion, our study unveils a clear PRDM1-regulated effector-memory cytotoxic CD8+ T cell footprint in plaque development and the shift from low- to high-risk plaques, thereby revealing CD8+ T cells and PRMD1 as potential targets for intervention in adverse T cell responses in human atherosclerotic lesions.

Total hip replacement: a retrospective multicentric analysis on re-intervention rate after single component revision

Total hip arthroplasty (THA) revision is a procedure consisting in the replacement of a single or multiple implant components and could take place once or more times (re-revision). The aim of this multicentre study is to evaluate the benefits of single component revision in respect of the principles that define implant stability. Two hundred and forty-two patients underwent THA revision at Orthopaedic Clinic of Pisa and Versilia (ITA) from January 2007 to December 2016. We have systematically excluded revisions due to septic or traumatic prosthesis loosening, revisions of both implant components (cotyle and stem) and replacement alone. To evaluate implant stability, we used preoperative X ray and intra-operative mechanical stress tests, applying accredited criteria. Two hundred and twenty-six patients (93%) underwent a single procedure of THA revision: 193 had cotyle replacement and 33 had femoral stem replacement. The remaining 16 (7 %) underwent at least two procedures: 10 of them had consecutive failure of the same component, while the other 6 had revision of the other component after the first procedure. Considering our cases series, we can assert that single component revision is the best choice when no signs of loosening are present on the remaining component. Nevertheless, an accurate evaluation with unanimous radiological criteria and intraoperative testing is essential for the surgeon to choose the most suitable treatment.

K+ Accumulation and Clearance in the Calyx Synaptic Cleft of Type I Mouse Vestibular Hair Cells

Vestibular organs of Amniotes contain two types of sensory cells, named Type I and Type II hair cells. While Type II hair cells are contacted by several small bouton nerve terminals, Type I hair cells receive a giant terminal, called a calyx, which encloses their basolateral membrane almost completely. Both hair cell types release glutamate, which depolarizes the afferent terminal by binding to AMPA post-synaptic receptors. However, there is evidence that non-vesicular signal transmission also occurs at the Type I hair cell-calyx synapse, possibly involving direct depolarization of the calyx by K⁺ exiting the hair cell. To better investigate this aspect, we performed whole-cell patch-clamp recordings from mouse Type I hair cells or their associated calyx. We found that [K⁺] in the calyceal synaptic cleft is elevated at rest relative to the interstitial (extracellular) solution and can increase or decrease during hair cell depolarization or repolarization, respectively. The change in [K⁺] was primarily driven by G_K,L, the low-voltage-activated, non-inactivating K⁺ conductance specifically expressed by Type I hair cells. Simple diffusion of K⁺ between the cleft and the extracellular compartment appeared substantially restricted by the calyx inner membrane, with the ion channels and active transporters playing a crucial role in regulating intercellular [K⁺]. Calyx recordings were consistent with K⁺ leaving the synaptic cleft through postsynaptic voltage-gated K⁺ channels involving K_V1 and K_V7 subunits. The above scenario is consistent with direct depolarization and hyperpolarization of the calyx membrane potential by intercellular K⁺.

Cross-validation of the RT-QuIC assay for the antemortem detection of chronic wasting disease in elk

Chronic wasting disease is a progressively fatal, horizontally transmissible prion disease affecting several members of the cervid species. Conventional diagnosis relies on ELISA or IHC evaluation using tissues collected post-mortem; however, recent research has focused on newly developed amplification techniques using samples collected antemortem. The present study sought to cross-validate the real-time quaking-induced conversion assay (RT-QuIC) evaluation of rectal biopsies collected from an elk herd with endemic CWD, assessing both binary positive/negative test results as well as relative rates of amplification between laboratories. We found that results were correlative in both categories across all laboratories performing RT-QuIC, as well as to conventional IHC performed at a national reference laboratory. A significantly higher number of positive samples were identified using RT-QuIC, with results seemingly unhindered by low follicle counts. These findings support the continued development and implementation of amplification assays in the diagnosis of prion diseases of veterinary importance, targeting not just antemortem sampling strategies, but post-mortem testing approaches as well.

Osteochondral avulsion fracture of the posteromedial tibial plateau

Posteromedial tibial plateau avulsion fracture caused by semimembranosus muscle is not easy to detect by X-ray. The literature regarding this issue is poor, also mechanism is extensively disputable. This lesion was often connected to an anterior cruciate ligament (ACL) rupture and medial meniscal horn lesion. In this work, we described a posteromedial tibial plateau avulsion fracture at the semimembranosus insertion. In particular, we referred to the surgical treatment of those transversal osteochondral fractures.

497 Multimodality imaging of an evergreen conundrum: true or false aneurysm of the left ventricle?

In case of transmural necrosis following STEMI, the myocardial wall may develop a true or false aneurysm. While the former usually has a benign course, the latter has a propensity to rupture leading to an ominous prognosis. We report the case of a patient with a recent inferior STEMI complicated with LV aneurysm of the inferior wall, initially diagnosed as a false aneurysm. We describe the case of a 77-year-old man affected by hypertension, diabetes and AF. Two months before he experienced an inferior STEMI treated with late (>12 hours from symptoms onset) pPCI and implantation of a DES on the RCA and the postero-lateral branch. TTE showed a mildly reduced LV systolic function (EF 50%) due to akinesia of the inferior wall. The patient presented to the ED for recurrent syncopes at rest. Vital signs were unremarkable. Troponin and electrolytes were within normal range. ECG showed a normofrequent sinus rhythm and Q waves with persistent ST elevation in the inferior leads. TTE showed a suspected rupture of the inferior wall in the middle segment between the posterolateral papillary muscle and the mitral annulus. The rupture seemed to be contained by the pericardium so as to create a huge cavity communicating with the LV through an apparently small neck and refurnished with turbolent blood during the cardiac cycle. In the suspicion of a pseudoaneurysm ( an urgent cardiac CT was performed. CT showed an extraventricular cavity apparently contained by the pericardium with a narrow neck and a pericardial effusion of a high density liquid. A diagnosis of post-infarction pseudoaneurysm was made. The day after the patient was stable but TTE showed a mild increase of the size of the "pseudoaneurysm", hence the Heart Team referred the patient to the cardiac surgery department for an urgent repair. In the surgical room TOE displayed the large cavity rising from the inferior wall of the LV and the communication thorugh a large neck. The intraoperatory finding was, unexpectedly, a true aneurysm of the inferior wall. The redundant aneurysm was excised and the defect was succesfully closed with a bovine pericardium patch. No periprocedural complication was recorded and the postoperatory period was uneventful. The present case strikingly shows how a mechanical complication may develop in spite of myocardial revascularization. The high level of suspicion led to a strong effort to achieve a definite diagnosis. Multimodality imaging plays a pivotal role and is warranted since the initial evaluation with TTE may be inconclusive. CT has a high diagnostic yield but false positives may happen. MRI could have been more specific in our case, but the clinical evolution and the CT images led us to be confident in referring the patient to an urgent cardiac surgery. In conclusion, the non invasive differential diagnosis between true and false aneurysm still remains a modern challenge.

Abstract 497 Figure. Multimodality imaging of a LV aneurysm

Distinct chromatin structures at the monoamine oxidase-A promoter correlate with allele-specific expression in SH-SY5Y cells

Monoamine oxidase-A (MAOA) metabolises monoamines and is implicated in the pathophysiology of psychiatric disorders. A polymorphic repetitive DNA domain, termed the uVNTR (upstream variable number tandem repeat), located at the promoter of the MAOA gene is a risk factor for many of these disorders. MAOA is on the X chromosome suggesting gender could play a role in regulation. We analysed MAOA regulation in the human female cell line, SH-SY5Y, which is polymorphic for the uVNTR. This heterozygosity allowed us to correlate allele-specific gene expression with allele-specific transcription factor binding and epigenetic marks for MAOA. Gene regulation was analysed under basal conditions and in response to the mood stabiliser sodium valproate. Both alleles were transcriptionally active under basal growth conditions; however, the alleles showed distinct transcription factor binding and epigenetic marks at their respective promoters. Exposure of the cells to sodium valproate resulted in differential allelic expression which correlated with allele-specific changes in distinct transcription factor binding and epigenetic marks at the region encompassing the uVNTR. Biochemically our model for MAOA promoter function has implications for gender differences in gene × environment responses in which the uVNTR has been implicated as a genetic risk.

Pharmacological differences and clinical implications of various botulinum toxin preparations: a critical appraisal

Three different type A botulinum neurotoxins (BoNTAs) - onabotulinumtoxinA, abobotulinumtoxinA and incobotulinumtoxinA) - are currently marketed in Europe to treat several conditions. Differences between BoNTA preparations, which depend on their specific biotypes and manufacturing processes, lead to clinically relevant pharmacotherapeutic dissimilarities. All three available products are separately recognized and reviewed in American Academy of Neurology guidelines. The neurotoxin load/100U is likewise different among the different BoNTAs, with the result that the specific potency of the 150kD BoNTA neurotoxin is calculated as 137 units/ng for onabotulinumtoxinA, 154 units/ng for abobotulinumtoxinA, and 227 units/ng for incobotulinumtoxinA. It is important for clinicians to have all three BoNTAs available in order to choose the most suitable preparation for the specific indication in the single patient. Commercially available BoNTAs must be recognized as different from one another, and therefore as non-interchangeable. The essential experience of the clinician is of the utmost importance in choosing the most appropriate treatment.

Enabling valley selective exciton scattering in monolayer WSe2 through upconversion

Excitons, Coulomb bound electron–hole pairs, are composite bosons and their interactions in traditional semiconductors lead to condensation and light amplification. The much stronger Coulomb interaction in transition metal dichalcogenides such as WSe₂ monolayers combined with the presence of the valley degree of freedom is expected to provide new opportunities for controlling excitonic effects. But so far the bosonic character of exciton scattering processes remains largely unexplored in these two-dimensional materials. Here we show that scattering between B-excitons and A-excitons preferably happens within the same valley in momentum space. This leads to power dependent, negative polarization of the hot B-exciton emission. We use a selective upconversion technique for efficient generation of B-excitons in the presence of resonantly excited A-excitons at lower energy; we also observe the excited A-excitons state 2s. Detuning of the continuous wave, low-power laser excitation outside the A-exciton resonance (with a full width at half maximum of 4 meV) results in vanishing upconversion signal.

Monolayer transition metal dichalcogenides host excitons, bound electron-hole pairs that play a pivotal role in optoelectronic applications relying on strong light-matter interaction. Here, the authors unveil the spectroscopic signature of boson scattering of two-dimensional excitons in monolayer WSe₂.

Influence of alkoxy chain envelopes on the interfacial photoinduced processes in tetraarylporphyrin-sensitized solar cells

We have investigated the effect of the alkoxy chain length and nature on the reduction of dye-to-dye aggregation as well as on the enhancement of light harvesting capabilities.

Does robot-assisted gait training ameliorate gait abnormalities in multiple sclerosis? A pilot randomized-control trial

BACKGROUND

Gait disorders are common in multiple sclerosis (MS) and lead to a progressive reduction of function and quality of life.

OBJECTIVE

Test the effects of robot-assisted gait rehabilitation in MS subjects through a pilot randomized-controlled study.

METHODS

We enrolled MS subjects with Expanded Disability Status Scale scores within 4.5-6.5. The experimental group received 12 robot-assisted gait training sessions over 6 weeks. The control group received the same amount of conventional physiotherapy. Outcomes measures were both biomechanical assessment of gait, including kinematics and spatio-temporal parameters, and clinical test of walking endurance (six-minute walk test) and mobility (Up and Go Test).

RESULTS

16 subjects (n = 8 experimental group, n = 8 control group) were included in the final analysis. At baseline the two groups were similar in all variables, except for step length. Data showed walking endurance, as well as spatio-temporal gait parameters improvements after robot-assisted gait training. Pelvic antiversion and reduced hip extension during terminal stance ameliorated after aforementioned intervention.

CONCLUSIONS

Robot-assisted gait training seems to be effective in increasing walking competency in MS subjects. Moreover, it could be helpful in restoring the kinematic of the hip and pelvis.

Combined strategy to realize efficient photoelectrodes for low temperature fabrication of dye solar cells

We implemented a low-temperature approach to fabricate efficient photoanodes for dye-sensitized solar cells, which combines three different nanoarchitectures, namely, a highly conductive and highly transparent AZO film, a thin TiO2-blocking layer, and a mesoporous TiO2 nanorod-based working electrode. All the components were processed at T≤200°C. Both the AZO and the TiO2 blocking layers were deposited by reactive sputtering, whereas the TiO2 nanorods were synthesized by surfactant-assisted wet-chemical routes and processed into photoelectrodes in which the native geometric features assured uniform mesoporous structure with effective nanocrystal interconnectivity suitable to maximize light harvesting and electron diffusion. Because of the optimized structure of the TiO2-blocking/AZO bilayer, and thanks to the good adhesion of the TiO2 nanorods over it, a significant enhancement of the charge recombination resistance was demonstrated, this laying on the basis of the outstanding power conversion efficiency achievable through the use of this photoanode's architecture: a value of 4.6% (N719) was achieved with a 4-μm-thick electrode processed at T=200°C. This value noticeably overcomes the current literature limit got on AZO-based cells (N719), which instead use Nb-doped and thicker blocking layers, and thicker nanostructured photoanodes, which have been even sintered at higher temperatures (450-500°C).

An engineered co-sensitization system for highly efficient dye solar cells

Novel co-sensitizers have been structurally tailored and implemented in multi-sensitized devices demonstrating synergic efficiency enhancement.

Estimation of spatial-temporal gait parameters in level walking based on a single accelerometer: validation on normal subjects by standard gait analysis

This paper investigates the ability of a single wireless inertial sensing device stuck on the lower trunk to provide spatial-temporal parameters during level walking. The 3-axial acceleration signals were filtered and the timing of the main gait events identified. Twenty-two healthy subjects were analyzed with this system for validation, and the estimated parameters were compared with those obtained with state-of-the-art gait analysis, i.e. stereophotogrammetry and dynamometry. For each side, from four to six gait cycles were measured with the device, of which two were validated by gait analysis. The new acquisition system is easy to use and does not interfere with regular walking. No statistically significant differences were found between the acceleration-based measurements and the corresponding ones from gait analysis for most of the spatial-temporal parameters, i.e. stride length, stride duration, cadence and speed, etc.; significant differences were found for the gait cycle phases, i.e. single and double support duration, etc. The system therefore shows promise also for a future routine clinical use.

Neuropeptide F peptides act through unique signaling pathways to affect cardiac activity

Elucidating how neuropeptides affect physiology may result in delineating peptidergic mechanisms and identifying antagonists for application in basic and translational science. Human neuropeptide Y (NPY) regulates cardiac activity; frequently invertebrates contain orthologs of vertebrate peptides. We report invertebrate NPY-like neuropeptide F (NPF) arrested the signal frequency of the slow phase of the cardiac cycle (EC50 = 1 pM); however, signal frequency of the fast phase was affected only minimally. Neuropeptide F decreased the duration of the slow phase by ~70% (EC50 = 0.6 pM), but increased the duration of the fast phase by ~57% (EC50 = 10nM). Short NPF-1 (sNPF-1) decreased the signal frequency of the slow phase by ~70% (EC50 = 9 nM); yet, signal frequency of the fast phase was unaffected. Short NPF-1 decreased the duration of the slow phase ~55% (EC50 ~50 nM), but increased the duration of the fast phase ~20% without dose dependency. Neuropeptide F and sNPF-1 increased isoelectric period duration. This novel report demonstrated NPY-like peptides are cardioactive but functionally unique. These data contribute to understanding how invertebrate orthologs affect cardiovascular activity. Dipteran fast and slow phases may be generated from separate pacemakers in the abdominal heart and in the anterior thoracocephalic aorta, respectively. Thus, our research suggests NPF and sNPF-1 act through different mechanisms to regulate cardiac activity. Invertebrate NPY-like peptides act in olfaction and feeding yet mechanisms which are associated with their cardioactive effects remain unknown; our work may provide evidence linking their roles in sensory response and cardiac activity.

Prevalence and clinical correlates of deliberate self-harm among a community sample of Italian adolescents

The aims of this study were to investigate the rates of deliberate self-harm (DSH) behavior among an Italian adolescent sample, as well as to explore its clinical correlates. On a sample of 234 adolescents in Italian secondary schools (Mean age = 16.47; SD = 1.7) were assessed the DSH as well as externalizing symptoms (including both conduct disorder [CD] and oppositional defiant disorder [ODD] symptoms), borderline personality disorder [BPD] symptoms, dissociative symptoms, and the incidence of life-stressors. Consistent with past research on DSH in youth, 42% of the adolescents in this sample engaged in DSH. Results indicate a positive association between DSH and all psychopathological correlates, including BPD, dissociative, and ODD and CD symptoms. Further, findings revealed an association between DSH and specific life-stressors (i.e., psychological and sexual abuse, natural disasters and serious accidents, the loss of someone important, and the witnessing of family violence or a serious accident).

Botulinum toxin type A versus phenol. A clinical and neurophysiological study in the treatment of ankle clonus

AIM

To reduce ankle clonus in patients with spastic paresis either phenol nerve block of the tibialis posterior nerve or botulinum toxin type A (BTA) injection in triceps surae muscles can be used. This study aims to compare the efficacy over time of phenol nerve block and BTA injection in the inhibition of ankle clonus.

METHODS

Twenty-two patients with spastic paresis presenting with ankle clonus were randomly treated with phenol nerve block of the tibialis posterior nerve or BTA injection in triceps surae muscles. Ankle passive dorsiflexion, clonus, M and H responses and H/M ratio were measured in all patients prior to treatment and 15 days afterwards, as well as one, three and six months later in 12 patients. Patient satisfaction was also recorded.

RESULTS

Both patient groups showed significant clonus reduction over time with the effect of phenol being greater than that of BTA. In one month, the degree of passive dorsiflexion significantly increased in both groups without any significant difference between them. H/M ratio reduced after phenol treatment and remained almost constant during the following six months, whereas it remained at baseline level after BTA treatment.

CONCLUSION

While both treatments led to reduction in ankle clonus, phenol showed greater clinical efficacy. The difference in the neurophysiological results suggests that the two drugs have different action mechanisms with a more prevalent reduction of alpha motoneuron excitability in phenol-treated patients.

Sagittal plane kinematic analysis of the six-minute walk test: a classification of hemiplegic gait

AIM

The aim of this study was to propose a kinematic classification of gait according to six minute walk test performance.

METHODS

Thirty-four hemiplegic subjects were enrolled. Six-minute walk test (SMWT), gait analysis and Walking Handicap Scale score (WHS) were measured. A k-means cluster analysis was used to classify the sample into three sub-groups which were homogeneous in spatio-temporal parameters, kinematic variables, and which reflected three meaningful levels of walking competency.

RESULTS

Three clusters were identified: low-functioning walkers (Cluster 1) walked for 88-172 m; intermediate-functioning walkers (Cluster 2) walked for 180-302 m and high-functioning walkers (Cluster 3) were able to cover 349-430 m. The authors found homogeneous gait profiles in these subgroups. Between-group differences on kinematic data and WHS scores were also underlined.

CONCLUSIONS

Cluster analysis was able to identify consistent gait characteristics of spatio-temporal, walking endurance and sagittal plane kinematic profiles in hemiplegic subjects and is useful for categorizing the levels of walking competency in these subjects.

The treatment of stable and unstable proximal femoral fractures with a new trochanteric nail: results of a multicentre study with the Veronail

The incidence of hip fractures continues to rise. This study is the first evaluation of a new intramedullary implant, the Veronail, that provides double axis fixation into the femoral head and allows the surgeon to choose whether to use sliding or fixed locked proximal screw fixation for trochanteric femoral fractures. The fractures were classified according to the AO classification, and function was assessed with the Modified Harris Hip Score. 111 patients with trochanteric fractures were evaluated in eight Italian hospitals. The stable 31.A1 fractures were treated with sliding proximal screws, the subtrochanteric 31.A3 fractures with converging proximal screws, and the unstable 31.A2 fractures were treated with both types of proximal fixation. The unstable fractures treated with locked converging screws had the same function at one year as those treated with sliding screws. This study suggests a possible new method of treating unstable trochanteric femoral fractures. This may be the solution to prevent excessive collapse of the fracture with the resultant poor function and persisting pain noted in the literature. Two converging locked proximal screws seem to provide stable fixation in 31.A2 femoral fractures and produce as good a result as the use of traditional sliding screws. The role of converging locked proximal screws in unstable trochanteric fractures requires further evaluation.

The upper limb in cerebral palsy: surgical management of shoulder and elbow deformities

The authors report a simple chart that offers a comprehensive picture of spasticity of the upper limb and provides a more objective method of recording data. Distinction is made between fixed postures and the residual active range of motion at the shoulder and elbow. The presence and function of the muscles can be identified easily on dynamic EMG studies, which are essential for understanding the degree of spasticity and dyssynergy related to a single muscle. When spasticity of the upper arm is managed with a global approach and objectives are defined clearly in advance with the patient and caregivers, treatment of shoulder and elbow deformities can achieve important results for personal hygiene or functional targets.

An estimate of the current risk of transmitting blood-borne infections through blood transfusion in Italy

We conducted a retrospective cohort study to estimate the incidence of major blood-borne agents among Italian blood donors and calculated the risk of infection among blood recipients using the 'incidence/window period model'. The study was conducted among 46 180 blood donors enrolled in six blood centres between 1994 and 1999. During follow-up, seven new infections were confirmed: three donors seroconverted for anti-human immunodeficiency virus (HIV); two for anti-hepatitis C virus (HCV); and two showed hepatitis B surface antigen (HBsAg) reactivity; no cases of syphilis were observed. The incidence rates per 100 000 person/years were: 4.06 (95% CI: 0.82-11.85) for HIV; 2.41 (95% CI: 0.29-8.70) for HCV; and 2.70 (95% CI: 0.32-9.77) for HBsAg; the incidence for total hepatitis B virus (HBV) infection was 9.77 per 100 000 person/years (95% CI: 1.16-35.36). The estimated risk of an infectious blood unit not being detected was: 2.45 (95% CI: 0.13-12.33) per 1 million units for HIV; 4.35 (95% CI: 0.30-22.39) for HCV; and 15.78 (95% CI: 1.16-84.23) for HBV. Overall, an estimated 22.58 per 1 million units are infected. In Italy, the risk of transfusion-transmitted infections is low and is similar to that in other western countries. The introduction of new more sensitive screening tests could reduce the residual risk of transfusion-transmitted infection by 40-80%.

Epidemiology of myotonic dystrophy in Italy: re-apprisal after genetic diagnosis

Before the discovery of the myotonic dystrophy (DM) gene, the DM epidemiological rates could not be accurately estimated. The aim of this study was to calculate the DM prevalence rates in Padova (North-East Italy) and in four provinces of North-West Tuscany (Central Italy) and, as of 30 June 1999, to do so using molecular genetic testing. A minimum prevalence rate of 9.31x10(-5) inhabitants was found, consistent with epidemiological rates worldwide, and more than two times as high as those of two previous studies conducted in the same areas during the era prior to molecular genetic testing. This study, the first in Italy since the discovery of the DM gene, underlines the importance of direct genetic diagnosis of DM, especially in detecting mildly affected patients, a fundamental step in correctly estimating the risk of disease transmission in affected families.

Improvement of the bone-pin interface strength in osteoporotic bone with use of hydroxyapatite-coated tapered external-fixation pins. A prospective, randomized clinical study of wrist fractures

BACKGROUND

Achieving adequate fixation strength in osteoporotic bone is a challenge. In this study, we examined the use of hydroxyapatite-coated tapered external-fixation pins for the fixation of wrist fractures in patients with osteoporosis.

METHODS

Twenty female patients with osteoporosis and a fracture of the wrist were divided into two paired groups and randomized to receive either standard tapered pins or hydroxyapatite-coated tapered pins. Two pins were inserted in the distal part of the radius, two pins were inserted in the second metacarpal, and an external fixation device was mounted. All fixation devices were removed six weeks after surgery.

RESULTS

The mean pin-insertion torque (and standard deviation) was 461 +/- 254 Nmm in the group managed with standard pins and 332 +/- 176 Nmm in the group managed with hydroxyapatite-coated pins (p = 0.01). The mean pin-extraction torque was 191 +/- 155 Nmm in the group managed with standard pins and 600 +/- 214 Nmm in the group managed with hydroxyapatite-coated pins (p < 0.0001, power 95%). The mean extraction torque was lower than the corresponding insertion torque at each pin position in the group managed with standard pins (p < 0.05), whereas the mean extraction torque was higher than the corresponding insertion torque at each pin position in the group managed with hydroxyapatite-coated pins (p = 0.001). Two patients managed with standard pins and no patient managed with hydroxyapatite-coated pins had a pin-track infection. Pain during pin removal did not differ between the two groups.

CONCLUSIONS

The present study showed that hydroxyapatite-coated tapered external-fixation pins provided improved fixation in the treatment of wrist fractures in patients with osteoporosis.

Handgrip strength is an independent predictor of distal radius bone mineral density in postmenopausal women

Several cross-sectional studies have reported a positive correlation between muscle strength and local bone mineral density. However, very few studies have evaluated the possible role of confounding variables, which may be substantial as both bone mineral density and muscle strength are multifactorial variables. We studied 140 postmenopausal women who underwent their first osteodensitometry in our hospital. Of these, 102 women affected neither by bone diseases apart from primary osteoporosis nor treated with drugs affecting bone mass were selected. Distal radius bone mineral density of the non-dominant arm was assessed by dual photon absorptiometry. Handgrip strength was measured by a handheld dynamometer. The following factors influencing bone mass were also considered: age, years since menopause, years of cyclic ovarian activity, body weight, body height, body mass index, and both calcium and alcohol dietary intake. Statistical evaluation was performed by stepwise multiple regression analysis. This showed that only two variables were independently related to bone mineral density: handgrip strength (which was the best bone density predictor among the studied independent variables) and years since menopause. R2 value was 0.43 (F=38.04, p < 0.001). All the other variables studied were not significantly related to bone density when the effects of both strength and years since menopause were considered. In conclusion, the data showed that handgrip strength was a strong independent predictor of distal radius bone mineral density in postmenopausal women. Clinical assessment of osteoporosis risk factors, including muscle strength, is recommended: although it is not an adequate substitute for bone densitometry, it can help clinicians to identify the risk groups at which to direct bone density measurement.

Prolonged prophylaxis with unfractioned heparin is effective to reduce delayed deep vein thrombosis in total hip replacement

The aim of this study was to assess the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) until 45 days after elective total hip replacement (THR) and the efficacy of prolonged unfractioned heparin (UH) prophylaxis up to postoperative day 30. To this end 79 of 96 patients admitted consecutively to the University Hospital of Pisa for THR were randomly assigned to short- or long-term UH prophylaxis. Sixty-one patients completed the study: 28 of them received short-term prophylaxis (subcutaneous UH 15,000 IU/24 h for 15 days) and 33 prolonged prophylaxis (subcutaneous UH 15,000 IU/24 h for 30 days). Lower limb phlebography was performed in all patients on day 45 after THR. DVT was demonstrated in 10 (16.3%) cases after hospital discharge. Among them, 2 patients also had symptomatic PE. The incidence of DVT was 21.4% in short- and 12.1% in long-term UH-treated patients. The incidence of only proximal DVT was 17.8% in short- and 3.0% in long-term UH-treated patients; although the difference was only close to significance (p = 0.085), the relative risk of developing proximal DVT was about six times greater in the former group of patients. We concluded that the risk for thromboembolism persists at least until 45 days after surgery in patients subjected to THR. Prophylaxis with UH given up to postoperative day 30 appears more effective and safer in reducing the delayed thromboembolic risk compared to prophylaxis with UH given up to discharge only.

Clinical validation of the avidin/indium-111 biotin approach for imaging infection/inflammation in orthopaedic patients

We report here the results of a validation study of the avidin/indium-111 biotin approach in patients with skeletal lesions. This study involved 54 patients with orthopaedic conditions: 20 patients with intermediate suspected osteomyelitis of the trunk, 19 patients with infection/inflammation of prosthetic joint replacements, and 15 patients with suspected osteomyelitis of appendicular bones. Avidin (3 mg) was injected as an i.v. bolus, followed 4 h later by 111In-biotin; imaging was acquired 30 min and 16-18 h after administration of 111In-biotin. Technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO)-labelled leucocyte scintigraphy was performed in 39/54 patients. The overall sensitivity of the avidin/111In-biotin scan was 97.7% (versus 88.9% for 99mTc-HMPAO leucocyte scintigraphy). While the diagnostic performance of avidin/111In-biotin scintigraphy was similar to that of 99mTc-HMPAO leucocyte scintigraphy in patients with prosthetic joint replacements or osteomyelitis of appendicular bones, the avidin/111In-biotin approach clearly performed better than 99mTc-HMPAO leucocyte scintigraphy in patients with suspected osteomyelitis of the trunk (100% sensitivity, specificity and accuracy versus 50% sensitivity, 100% specificity and 66.7% accuracy for 99mTc-HMPAO-leucocyte scintigraphy). These results demonstrate the feasibility of the avidin/111In-biotin approach for imaging sites of infection/inflammation in the clinical setting. Although no systematic advantages of avidin/111In-biotin scintigraphy were found versus 99mTc-HMPAO leucocyte scintigraphy, the newer scintigraphic method is more practicable and involves lower biological risk for the operators.

H reflex excitability following voluntary muscle contraction of different duration

The importance of the duration of contraction on the excitability of the motoneuronal pool was evaluated by measuring the H reflex from soleus muscle after short and long contractions at constant effort equal to 60% maximal voluntary contraction (MVC); the difference between the amplitude of H reflex at rest and after contraction of different duration was evaluated in 10 normal subjects and in one hemiparetic patient. The authors found a significant inhibition of H reflex after contraction of 10 seconds and after 40 seconds and a longer duration of the inhibition after 40 seconds. In the hemiparetic patient the H reflex did not show inhibition which suggests a possible reduction of the presynaptic inhibition, and a lack of modulation of the motoneuronal pool after contraction.

[High-resolution electrocardiography in 102 young healthy subjects]

BACKGROUND

The aim of this study was to evaluate the normal values of the most common indexes used in the analysis of ventricular late potential in 102 young male subjects.

METHODS

The recordings were performed by means of a Marquette electronics Hi-Resolution ECG Mac 15, with filters at 25-250 Hz, 40-250 Hz and 80-250 Hz. The parameters obtained were: filtered QRS duration (QRSD), high-frequency low-amplitude signals duration (HFLA), and the root mean square of the signal expressed in the terminal portion of QRS (RMS). The body surface was also evaluated.

RESULTS

QRSD (121.23 ms-113.9 ms-99.9 ms); RMS (105 uV-42.77 uV-34.3 uV); HFLA (17.5 ms-29.3 ms-29.3 ms). The comparison between our results and those proposed by other authors for normal subjects showed different results, particularly concerning the filtered QRS duration. We suppose that these discrepancies may be due to the different instrumentations used and to the different age and sex of the study population.

CONCLUSIONS

From these results we confirm that a normal range for each index must be done for homogeneous groups of subjects for age and sex, in healthy subjects as well as for different heart disease.

[Discordance between clinical and immunological aspects in a case of chronic B-type lymphoproliferative syndrome]

Chronic lymphoproliferative disorders are extremely heterogeneous from a clinical, morphological and immunological point of view. The paper reports the case of a woman with chronic prolymphocytic leukemia. The neoplastic clone revealed the typical immunological features of pre-B lymphocytes, which are at an earlier stage of differentiation in respect to prolymphocytes. After polychemotherapy (CEOP) the phenotype of the neoplastic cells shifted to an immunological pattern typical of B lymphocytes.

Antenatal diagnosis of beta-thalassemia by isoelectric focusing in immobilized ph gradients

A new method for antenatal diagnosis of thalassemias is reported based on the analysis of the major Hb components of fetal cord blood, sampled at week 18 of pregnancy under ultrasonic guidance, by isoelectric focusing in immobilized pH gradients (IPG). In an IPG gel encompassing a pH 6.7-7.6 span, HbA and HbFac are separated by a distance nine times greater than in a conventional carrier ampholyte pH 6-8 gel and three times greater than in an ampholine gel with separators (an equimolar mixture of beta-alanine and 6-amino caproic acid). Band evenness (in terms of uniform protein concentration within a zone) and straightness (in terms of parallel alignment of the bands to the electrodes), because of insensitivity of IPG gels to salt distortions, allows for accurate and reproducible quantitation of HbF, -A, and -Fac levels. The possibility of greatly overloading IPG matrices in total Hbs increases the sensitivity of the technique to the detection of only 0.5% HbA in the total Hb mixture, the lower limit of conventional IEF being only 2.5% HbA. Of 15 fetuses from couples at risk analyzed in the region of Ozieri, three were found to be homozygous beta-thalassemic, eight heterozygous, and four normal with no false-positives or -negatives.

Detection of electrophoretically silent mutations by immobilized pH gradients

The detection of neutral amino acid mutants, by isoelectric focusing in immobilized pH gradients (IPGs), is exemplified by the separation of hemoglobin (Hb) Beirut (126 beta Val----Ala) from Hb A in a shallow pH 7.2-7.6 IPG gradient with 2% Ampholine pH 6-8. The mechanism of these separations appears to involve minute alterations in the pK values of ionizable groups bordering the mutation site, which are in turn reflected in tiny alterations in the net surface charge, delta pI. The delta pI values are of the order of 0.01 to 0.001 pH units, outside the resolving limits of conventional isoelectric focusing, and correspond to changes of the order of 0.1-0.01 unit charge (a proton or an electron).

Pattern electroretinogram in multiple sclerosis

The pattern electroretinogram obtained in patients affected by multiple sclerosis were compared with those in a normal population. The pattern electroretinogram amplitude in multiple sclerosis optic neuritis frequently appeared normal, but pattern electroretinogram amplitude abnormalities were found in patients suffering from recurrent multiple sclerosis optic neuritis. Pattern electroretinogram examination appears a useful method in the differential diagnosis between axonal and demyelinating optic nerve impairment.

[The origin of the electroretinogram induced by structured stimuli in man]

The Authors studied the checkerboard pattern electroretinogram (PERG) behaviour in normal subjects and in patients suffering from traumatic lesion of optic nerve, demyelinating optic neuritis, axonal optic neuritis, retinal vascular disorders and retinitis pigmentosa in order to verify the PERG origin. According to our data the PERG appears to originate from ganglion cells since the signal diminished or disappeared in axonal lesion of optic nerve, as a result of retrograde ganglion cell degeneration. Furthermore, the demyelinating lesions of optic nerve were not able to modify the PERG wave. In patients suffering from retinal receptor disturbances the flash electroretinogram (FERG), which is probably an expression of receptor activity, was greatly impaired, whereas PERGs were either normal or less impaired than FERGs. These data demonstrate the different origin of PERG and FERG.

[The effect of fatigue on the biopotential of muscle fiber cells]

Muscular fatigue is a biological situation which is very difficult to quantify. The Authors studied through a computer analysis the power spectrum of electromyogram, recorded from abductor digiti minimi muscle during maximal and minimal contraction effort before and after fatigue and after muscle prolonged relaxation in 8 normal subjects. No significant spectrum differences were found between maximal and minimal effort in each trial, and between the spectra obtained before fatigue and after muscle prolonged relaxation. On the contrary significant differences were found between the spectra obtained after fatigue and the other conditions. The power spectrum analysis appears, also, to be a reliable neurophysiological parameter for the study of biological aspects of muscular fatigue.

[The effect of thoracic pressoreceptors on heart rate in man]

Sinus arrhythmia (SA) is a physiological event related to the respiratory activity. The aim of this study was to find a relation between SA and different deep breathings. A transductor monitored the chest respiratory movements and a cardiotachometer calculated and plotted the instantaneous heart rate, synchronously during different breathing efforts. In 10 normal subjects a good linear correlation was found between the breathing depth and SA quantifying the relation between the chest receptor activity and SA also with limited chest expansion.