Metal components of hip prostheses cause severe artifacts in CT images, influencing diagnostic accuracy. Metal artifact reduction (MAR) software and virtual monoenergetic reconstructions on ...dual-energy CT (DECT) systems are possible solutions that should be considered. In this study, we created a customized adjustable phantom to quantify the severity of artifacts on periprosthetic tissues (cortical and spongious bone, soft tissues) for hip prostheses. The severity of artifacts was classified by different thresholds of deviation from the CT numbers for reference objects not affected by artifacts. The in vitro setup was applied on four unilateral and three bilateral configurations of hip prostheses (made of titanium, cobalt, and stainless steel alloys) with a DECT system, changing the energy of virtual monoenergetic reconstructions, with and without MAR. The impact of these tools on the severity of artifacts was scored, looking for the best scan conditions for the different configurations. For titanium prostheses, the reconstruction at 110 keV, without MAR, always minimized the artifacts. For cobalt and stainless-steel prostheses, MAR should always be applied, while monoenergetic reconstruction alone did not show clear advantages. The available tools for reducing metal artifacts must therefore be applied depending on the examined prosthetic configuration.
Purpose
Single‐sided 1H‐NMR is proposed for the estimation of morphological parameters of trabecular bone, and potentially the detection of pathophysiological alterations of bone structure. In this ...study, a new methodology was used to estimate such parameters without using an external reference signal, and to study intratrabecular and intertrabecular porosities, with a view to eventually scanning patients.
Methods
Animal trabecular bone samples were analyzed by a single‐sided device. The Carr‐Purcell‐Meiboom‐Gill sequence of 1H nuclei of fluids, including marrow, confined inside the bone, was analyzed by quasi‐continuous T2 distributions and separated into two 1H pools: short and long T2 components. The NMR parameters were estimated using models of trabecular bone structure, and compared with the corresponding micro‐CT.
Results
Without any further assumptions, the internal reference parameter (short T2 signal intensity fraction) enabled prediction of the micro‐CT parameters BV/TV (volume of the trabeculae/total sample volume) and BS/TV (external surface of the trabeculae/total sample volume) with linear correlation coefficient >0.80. The assignment of the two pools to intratrabecular and intertrabecular components yielded an estimate of average intratrabecular porosity (33 ± 5)%. Using the proposed models, the NMR‐estimated BV/TV and BS/TV were found to be linearly related to the corresponding micro‐CT values with high correlation (>0.90 for BV/TV; >0.80 for BS/TV) and agreement coefficients.
Conclusion
Low‐field, low‐cost portable devices that rely on intrinsic magnetic field gradients and do not use ionizing radiation are viable tools for in vitro preclinical studies of pathophysiological structural alterations of trabecular bone.
Hutchinson–Gilford progeria syndrome (HGPS) causes premature aging in children, with adipose tissue, skin and bone deterioration, and cardiovascular impairment. In HGPS cells and mouse models, high ...levels of interleukin‐6, an inflammatory cytokine linked to aging processes, have been detected. Here, we show that inhibition of interleukin‐6 activity by tocilizumab, a neutralizing antibody raised against interleukin‐6 receptors, counteracts progeroid features in both HGPS fibroblasts and LmnaG609G/G609G progeroid mice. Tocilizumab treatment limits the accumulation of progerin, the toxic protein produced in HGPS cells, rescues nuclear envelope and chromatin abnormalities, and attenuates the hyperactivated DNA damage response. In vivo administration of tocilizumab reduces aortic lesions and adipose tissue dystrophy, delays the onset of lipodystrophy and kyphosis, avoids motor impairment, and preserves a good quality of life in progeroid mice. This work identifies tocilizumab as a valuable tool in HGPS therapy and, speculatively, in the treatment of a variety of aging‐related disorders.
Signs of premature ageing are improved by tocilizumab treatment. A study in a murine model of Hutchinson‐Gilford Progeria shows that neutralization of interleukin 6 preserves motor activity and slows‐down tissue deterioration.
HIV-infected subjects have high incidence rates of Staphylococcus aureus infections, with both methicillin-susceptible and methicillin-resistant (MRSA) strains. Possible explanations could include ...the high burden of colonization, the behavioral risk factors, and the frequent exposures to health care facilities of HIV-infected patients. The purpose of the study was to assess the risk factors for clinically- significant methicillin-resistant Staphylococcus aureus (CS-MRSA) infections in HIV-infected patients admitted to Infectious Diseases Units.
From January 1, 2002 to December 31, 2005, we conducted a retrospective case-control (1:2) study. We identified all the cases of CS-MRSA infections in HIV-infected patients admitted to the National Institute for Infectious Diseases (INMI) "Lazzaro Spallanzani" in the 4-year study period. A conditional logistic regression model was used to identify risk factors for CS-MRSA infection.
We found 27 CS-MRSA infections, i.e. 0.9 CS-MRSA infections per 100 HIV-infected individuals cared for in our Institute. At multivariate analysis, independent predictors of CS-MRSA infection were cumulative hospital stay, invasive procedures in the previous year, and low CD4 cell count. Particularly, the risk for CS-MRSA increased by 14% per an increase of 5 days hospitalization in the previous year. Finally, we identified a low frequency of community-acquired MRSA infections (only 1 of 27; 3.7%) among HIV-infected patients.
Clinicians should be aware of the risk for CS-MRSA infection in the clinical management of HIV-infected patients, especially in those patients with a low CD4 cell count, longer previous hospital stay, and previous invasive procedures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The transgenic LmnaG609G progeric mouse represents an outstanding animal model for studying the human Hutchinson-Gilford Progeria Syndrome (HGPS) caused by a mutation in the LMNA gene, coding for the ...nuclear envelope protein Lamin A/C, and, as an important, more general scope, for studying the complex process governing physiological aging in humans. Here we give a comprehensive description of the peculiarities related to the breeding of LmnaG609G mice over a prolonged period of time, and of many features observed in a large colony for a 2-years period. We describe the breeding and housing conditions underlining the possible interference of the genetic background on the phenotype expression. This information represents a useful tool when planning and interpreting studies on the LmnaG609G mouse model, complementing any specific data already reported in the literature about this model since its production. It is also particularly relevant for the heterozygous mouse, which mirrors the genotype of the human pathology however requires an extended time to manifest symptoms and to be carefully studied.
•We provide comprehensive information about long-term breeding of the G609G mice.•Peculiarities of progeria, behavior and quality of life of G609G mice are described.•Skeletal muscle alterations are described in heterozygous human-mirroring mice.•Bone mechanical competence in G609G heterozygous mice is described as first time ever.•Our report facilitates exploiting this progeric murine model for studies on aging.
Two cases of community-acquired septicemia caused by serotype-O1 Yersinia pseudotuberculosis were diagnosed in middle-aged, HIV-positive, immunodeficient patients during an 8-month period. Bacterial ...isolates were genetically indistinguishable, but no epidemiologic link between the 2 patients was established. HIV-related immunosuppression should be regarded as a risk factor for Y. pseudotuberculosis septicemia.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objective
The development of bipedalism is a very complex activity that contributes to shaping the anatomy of the foot. The talus, which starts ossifying in utero, may account for the developing ...stages from the late gestational phase onwards. Here, we explore the early development of the talus in both its internal and external morphology to broaden the knowledge of the anatomical changes that occur during early development.
Materials and Methods
The sample consists of high‐resolution microCT scans of 28 modern juvenile tali (from 36 prenatal weeks to 2 years), from a broad chronological range from the Late Roman period to the 20th century. We applied geometric morphometric and whole‐bone trabecular analysis to investigate the early talar morphological changes.
Results
In the youngest group (<6 postnatal months), the immature external shell is accompanied by an isotropic internal structure, with thin and densely packed trabeculae. After the initial attempts of locomotion, bone volume fraction decreases, while anisotropy and trabecular thickness increase. These internal changes correspond to the maturation of the external shell, which is now more defined and shows the development of the articular surfaces.
Discussion
The internal and external morphology of the human talus reflects the diverse load on the foot during the initial phases of the bipedal locomotion, with the youngest group potentially reflecting the lack of readiness of the human talus to bear forces and perform bipedal walking. These results highlight the link between mechanical loading and bone development in the human talus during the acquisition of bipedalism, providing new insight into the early phases of talar development.
We describe the first case of community-acquired bacteremia caused by Acinetobacter radioresistens; the patient was a 32-year-old HIV-positive neutropenic woman. Ambiguous Gram staining and poor ...biochemical reactivity of blood culture isolates misguided early diagnosis and therapy. Bacterial identification was based on 16S rDNA sequence analysis. A. radioresistens can be considered as a cause of opportunistic infection in immunodeficient patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objectives
The study of the development of human bipedalism can provide a unique perspective on the evolution of morphology and behavior across species. To generate new knowledge of these mechanisms, ...we analyze changes in both internal and external morphology of the growing human talus in a sample of modern human juveniles using an innovative approach.
Materials and Methods
The sample consists of high‐resolution microCT scans of 70 modern juvenile tali, aged between 8 postnatal weeks and 10 years old, from a broad chronological range from Middle/Late Neolithic, that is, between 4800 and 4500 BCE, to the 20th century. We applied geometric morphometric and whole‐bone trabecular analysis (bone volume fraction, degree of anisotropy, trabecular number, thickness, and spacing) to all specimens to identify changes in the external and internal morphology during growth. Morphometric maps were also generated.
Results
During the first year of life, the talus has an immature and globular shape, with a dense, compact, and rather isotropic trabecular architecture, with numerous trabeculae packed closely together. This pattern changes while children acquire a more mature gait, and the talus tends to have a lower bone volume fraction, a higher anisotropy, and a more mature shape.
Discussion
The changes in talar internal and external morphologies reflect the different loading patterns experienced during growth, gradually shifting from an “unspecialized” morphology to a more complex one, following the development of bipedal gait. Our research shows that talar plasticity, even though genetically driven, may show mechanical influences and contribute to tracking the main locomotor milestones.
This study evaluated the effects of low-dose cisplatin plus 89Sr versus 89Sr alone in the treatment of painful bone metastases from prostate cancer, addressing both pain palliation and cytostatic ...effects. Seventy patients with metastatic hormone-refractory prostate cancer were randomized into 2 groups: One group (arm A) received 148 MBq 89Sr plus 50 mg/m(2) cisplatin, and the other group (arm B) received 148 MBq 89Sr plus placebo. After treatment, the patients were followed up until death to evaluate the outcome variables: grade and duration of pain palliation, onset of new painful sites, changes in bone disease, global survival, serum prostate-specific antigen and alkaline phosphatase changes, and hematologic toxicity. Overall pain relief occurred in 91% of patients in arm A and 63% of patients in arm B (P < 0.01), with a median duration of 120 d in arm A and 60 d in arm B (P = 0.002). New painful sites on previously asymptomatic bone metastases appeared in 14% of patients in arm A and in 30% of patients in arm B (P = 0.18). The median survival without new painful sites was 4 mo in arm A and 2 mo in arm B (P = 0.04). Bone disease progression was observed in 27% of patients in arm A and in 64% of patients in arm B (P = 0.01). Median global survival after therapy was 9 mo in arm A and 6 mo in arm B (P = 0.30). Transient and moderate hematologic toxicity, as determined by World Health Organization criteria, was apparent in both arms without significant differences. The addition of a low dose of cisplatin enhances the effect of a standard dose of 89Sr without significant side effects, producing a significant improvement in pain palliation and a cytostatic effect on bone disease.
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