The regional pattern of age-related synaptic loss in the human brain differs from gray matter volume loss: in vivo PET measurement with [11C]UCB-J

PURPOSE

Aging is a major societal concern due to age-related functional losses. Synapses are crucial components of neural circuits, and synaptic density could be a sensitive biomarker to evaluate brain function. [11C]UCB-J is a positron emission tomography (PET) ligand targeting synaptic vesicle glycoprotein 2A (SV2A), which can be used to evaluate brain synaptic density in vivo.

METHODS

We evaluated age-related changes in gray matter synaptic density, volume, and blood flow using [11C]UCB-J PET and magnetic resonance imaging (MRI) in a wide age range of 80 cognitive normal subjects (21-83 years old). Partial volume correction was applied to the PET data.

RESULTS

Significant age-related decreases were found in 13, two, and nine brain regions for volume, synaptic density, and blood flow, respectively. The prefrontal cortex showed the largest volume decline (4.9% reduction per decade: RPD), while the synaptic density loss was largest in the caudate (3.6% RPD) and medial occipital cortex (3.4% RPD). The reductions in caudate are consistent with previous SV2A PET studies and likely reflect that caudate is the site of nerve terminals for multiple major tracts that undergo substantial age-related neurodegeneration. There was a non-significant negative relationship between volume and synaptic density reductions in 16 gray matter regions.

CONCLUSION

MRI and [11]C-UCB-J PET showed age-related decreases of gray matter volume, synaptic density, and blood flow; however, the regional patterns of the reductions in volume and SV2A binding were different. Those patterns suggest that MR-based measures of GM volume may not be directly representative of synaptic density.

Cortical atrophy distinguishes idiopathic normal-pressure hydrocephalus from progressive supranuclear palsy: A machine learning approach

INTRODUCTION

Progressive supranuclear palsy (PSP) and idiopathic normal pressure hydrocephalus (iNPH) share several clinical and radiological features, making the differential diagnosis challenging. In this study, we aimed to differentiate between these two diseases using a machine learning approach based on cortical thickness and volumetric data.

METHODS

Twenty-three iNPH patients, 50 PSP patients and 55 control subjects were enrolled. All participants underwent a brain 3T-MRI, and cortical thickness and volumes were extracted using Freesurfer 6 on T1-weighted images and compared among groups. Finally, the performance of a machine learning approach with random forest using the extracted cortical features was investigated to differentiate between iNPH and PSP patients.

RESULTS

iNPH patients showed cortical thinning and volume loss in the frontal lobe, temporal lobe and cingulate cortex, and thickening in the superior parietal gyrus in comparison with controls and PSP patients. PSP patients only showed mild thickness and volume reduction in the frontal lobe, compared to control subjects. Random Forest algorithm distinguished iNPH patients from controls with AUC of 0.96 and from PSP patients with AUC of 0.95, while a lower performance (AUC 0.76) was reached in distinguishing PSP from controls.

CONCLUSION

This study demonstrated a more severe and widespread cortical involvement in iNPH than in PSP, possibly due to the marked lateral ventricular enlargement which characterizes iNPH. A machine learning model using thickness and volumetric data led to accurate differentiation between iNPH and PSP patients, which may help clinicians in the differential diagnosis and in the selection of patients for shunt procedures.

Testicular volume loss in the long-term follow-up after surgical detorsion of the testis

AIM

The aim of this study is to evaluate sonographic testicular volume of patients who underwent surgical detorsion due to testicular torsion and to reveal the frequency of long-term testicular volume loss and the factors affecting it.

METHOD

The files of patients who underwent surgical detorsion due to unilateral testicular torsion in our hospital between 2011 and 2019 were reviewed retrospectively. Age at the time of detorsion surgery, time from the onset of pain to surgery, degree of torsion, and ultrasonographic testicular volumes before detorsion were noted. Afterward, patients with at least 6 months of follow-up were contacted by phone and testicular volumes were measured by scrotal ultrasonography (US). The sonographic formula Length × Width × Height × 0.72 was used to determine testicular volumes.

RESULTS

There were 97 patients who underwent surgical detorsion within the given time frame. However, 43 of these patients accepted to be involved in the study and a follow-up scrotal US was performed. The mean age at the time of detorsion was 13.6 ± 5.6 years, whereas it was 16.7 ± 6.2 years at the time of the follow-up visit. The median time from the onset of pain to surgery was 4 h (range 1-36 h). In the preoperative US, the mean volume of the affected testis was 10.8 ± 5.6 mm³, while the mean contralateral testis volume was 10.2 ± 5.4 mm³ (p = 0.134). The median follow-up time in our study was 24 months (range 6-96 months). In the control US, the mean volume of the affected testis was 9.5 ± 7.1 mm³, while the mean volume of the contralateral testis was 14.4 ± 9 mm³ (p = 0.001). The affected testicular volumes decreased in 23 patients (range 1.1-100%), there was no change in testicular volumes in two patients, and there was an increase in testicular volumes in 18 patients (range 3.8-100%). In the ROC analysis, risk of testicular volume loss can be predicted with 87.5% sensitivity and 83.9% specificity when the time from the onset of pain to surgery exceeds 5.5 h (AUC = 0.904).

CONCLUSION

Our results indicated that if the time from the onset of pain to surgery exceeds 5.5 h, the testicular volume loss may be expected in the long term. Thus, patients and parents should be informed accordingly.

The Physical Examination to Assess for Anemia and Hypovolemia

Hypovolemia develops with the loss of extracellular fluid volume or blood. Rapidly identifying hypovolemia can be lifesaving. Indicators of hypovolemia on examination include supine or postural hypotension, increase in heart rate by 30 beats per minute or severe dizziness with standing, and a decrease in central venous pressure detected on visual inspection of the jugular venous pressure or ultrasound assessment of the inferior vena cava or internal jugular veins. Other findings with utility include a dry axilla and dry oral mucosa. With chronic anemia, hemodynamic changes detectable on examination may be minimal, as the body compensates by retaining extracellular volume.

Effect of alumina particle morphology used for air abrasion on loss of enamel and luting composite resin

OBJECTIVE

To evaluate the volume loss after air abrasion with alumina particles with different morphology on bovine enamel and luting composite resin.

METHODS

Air abrasion was performed on 12 unscathed bovine teeth and 72 luting composite resin discs with 85 μm round-shaped and 50 μm sharp-edged alumina particles applied for 20 s, 40 s and 60 s (n = 12). Air abrasion was standardized by uniform areas of 2 mm diameter, a pressure of 0.25 MPa and a distance of 3 mm. The volume loss was determined by using a laboratory scanner.

RESULTS

Air abrasion with round-shaped alumina particles was mostly not measurable with the laboratory scanner, while sharp-edged alumina air abrasion resulted in significant loss of enamel. The median of volume loss by sharp-edged alumina particles ranged from 0.78 mm³ (20 s) to 2.52 mm³ (60 s). In contrast to round-shaped alumina the removal caused by sharp-edged alumina increased significantly with increasing application times (p ≤ 0.05). For air abrasion on luting composite resin the median of the removed volume ranged from 2.25 mm³ (20 s) to 6.18 mm³ (60 s), while round-shaped alumina showed a range from 0.45 mm³ (20 s) to 1.40mm³ (60 s). The round-shaped alumina produced a statistically significant lower volume loss than sharp-edged alumina for all three air abrasion times.

SIGNIFICANCE

The 85 μm round-shaped alumina particles removed less composite resin than 50 μm sharp-edged alumina particles but barely any enamel, making it an option for removing composite resin residues from enamel.

Volume reduction without neuronal loss in the primate pulvinar complex following striate cortex lesions

Lesions in the primary visual cortex (V1) cause extensive retrograde degeneration in the lateral geniculate nucleus, but it remains unclear whether they also trigger any neuronal loss in other subcortical visual centers. The inferior (IPul) and lateral (LPul) pulvinar nuclei have been regarded as part of the pathways that convey visual information to both V1 and extrastriate cortex. Here, we apply stereological analysis techniques to NeuN-stained sections of marmoset brain, in order to investigate whether the volume of these nuclei, and the number of neurons they comprise, change following unilateral long-term V1 lesions. For comparison, the medial pulvinar nucleus (MPul), which has no connections with V1, was also studied. Compared to control animals, animals with lesions incurred either 6 weeks after birth or in adulthood showed significant LPul volume loss following long (> 11 months) survival times. However, no obvious areas of neuronal degeneration were observed. In addition, estimates of neuronal density in lesioned hemispheres were similar to those in the non-lesioned hemispheres of same animals. Our results support the view that, in marked contrast with the geniculocortical projection, the pulvinar pathway is largely spared from the most severe long-term effects of V1 lesions, whether incurred in early postnatal or adult life. This difference can be linked to the more divergent pattern of pulvinar connectivity to the visual cortex, including strong reciprocal connections with extrastriate areas. The results also caution against interpretation of volume loss in brain structures as a marker for neuronal degeneration.

The Use of Tissue Adhesive for Tumor Bed Closure during Partial Nephrectomy is Associated with Reduced Devascularized Functional Volume Loss

Objectives

To quantitatively compare the functional renal volume loss, following nephron sparing surgery (NSS) between patients in whom tumor bed closure was done by biological tissue adhesive and those who were managed by standard suture technique.

Methods

From our institutional NSS database we retrospectively collected patients who had two sequential quantitative single-photon emission computed tomography of ^99mTc-dimercaptosuccinic acid uptake studies, the first study immediately before surgery and the second one 3-6 months following surgery. The study group included 69 patients: 26 (37.7%) patients in the sealant group (BioGlue®) and 43 (62.3%) patients in the standard suture group.

Results

No statistically significant differences were noted in the baseline clinical and pathological characteristics of the studied groups. However, there were several statistically significant differences in operative variables: patients in the suture group had larger amount of blood loss (3-fold), longer ischemia time (26.6 vs. 21 minutes,) and slightly longer operation time. Patients in whom tumor bed was closed by sutures had nearly 3-fold higher parenchymal loss compared to patients managed by sealant (26.28 vs. 8.92 ml, p = 0.048).

Conclusions

The use of tissue sealant during tumor bed reconstruction is associated with reduced devascularized parenchymal mass loss and should be considered among modifiable surgical factors during NSS.

The progressive wear and abrasiveness of novel graded glass/zirconia materials relative to their dental ceramic counterparts

OBJECTIVE

To investigate the wear behavior of novel graded glass/zirconia materials and their abrasiveness to the antagonist relative to homogeneous zirconias (polished or glazed) and a glass-ceramic.

METHODS

Graded glass/zirconia specimens were prepared by sintering with concurrent glass-infiltration of pre-sintered zirconia (3Y-TZP) with a polished or as-machined surface. Monolithic zirconia samples were sintered and their surfaces were polished or glazed (as-machined). Glass-ceramic samples were obtained and the surface polished. All specimens were subjected to chewing simulations with a steatite antagonist (r = 3 mm) and a cyclic load of 50 N. Quantitative measurements of wear and roughness were performed on ceramics and antagonists for prescribed number of cycles. Damage sustained in ceramics and antagonists was analyzed by SEM.

RESULTS

The polished zirconia presented little to no variation in wear depth (2 μm) and roughness (0.06 μm). Graded and glazed zirconia experienced a rapid increase in wear depth while the superficial glass layer was present (until 1000 cycles), but showed little variations afterwards - at 450k cycles ∼15 μm for graded and 78 μm for glazed zirconia. The glass-ceramic presented the greatest wear depth (463 μm) and roughness (1.48 μm). Polished zirconia, polished graded zirconia and glazed zirconia yielded significantly lower volumetric wear (∼3 mm3) of the antagonist than as-machined graded zirconia and glass-ceramic (∼5 mm3).

SIGNIFICANCE

Polished graded zirconia and polished zirconia presented little wear and roughness, as well as yielded reduced antagonist wear. Glassy materials are both more susceptible to wear and more abrasive to the antagonist relative to zirconia.

Objective Evaluation of Eyebrow Position After Autologous Fat Grafting to the Temple and Forehead

BACKGROUND

Fat grafting can be used to correct age-related volume loss in the face. However, the degree of rejuvenation is difficult to be evaluated.

OBJECTIVES

The author sought to objectively verify the change in patients' eyebrow position after fat grafting to the upper face.

METHODS

The charts of 175 consecutive patients who underwent autologous fat grafting to the forehead and temple were reviewed. Perioperative changes in the heights of medial, middle, and lateral segments of the eyebrow and the eyebrow slant were recorded and compared. Key prevention strategies to avoid potential complications were discussed.

RESULTS

The eyebrow slant was increased by 2.4° after the operation which was statistically significant (p < 0.05). On the other hand, the medial eyebrow height was decreased, while the middle and lateral eyebrow heights were increased after the surgery which were of no significance. No major complications such as vision loss or vascular compromise were noted.

CONCLUSIONS

Simultaneous autologous fat grafting to the temple and forehead significantly increased the slant of the eyebrows and corrected the loss of upper facial fullness as well. Collectively, these changes made the patient look younger and aesthetically more pleasant.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Technical note: Computer-manufactured inserts for prosthetic sockets

The objective of this research was to use computer-aided design software and a tabletop 3-D additive manufacturing system to design and fabricate custom plastic inserts for trans-tibial prosthesis users. Shape quality of inserts was tested right after they were inserted into participant's test sockets and again after four weeks of wear. Inserts remained properly positioned and intact throughout testing. Right after insertion the inserts caused the socket to be slightly under-sized, by a mean of 0.11mm, approximately 55% of the thickness of a nylon sheath. After four weeks of wear the under-sizing was less, averaging 0.03mm, approximately 15% of the thickness of a nylon sheath. Thus the inserts settled into the sockets over time. If existing prosthetic design software packages were enhanced to conduct insert design and to automatically generate fabrication files for manufacturing, then computer manufactured inserts may offer advantages over traditional methods in terms of speed of fabrication, ease of design, modification, and record keeping.

Midface sculpting with autologous fat

There is currently a major paradigm shift from excision-based surgery to strictly volume enhancement. Because there is still no perfect facial filler, development of synthetic facial injectables continue to advance at a remarkable pace. Each type of filler carries a specific characteristic that makes it more suitable for a certain clinical application. The continuing change in facial fillers offers the possibility for volume augmentation procedures with less downtime and without the need for harvesting fat. We predict that volume enhancement will continue to play an increasing role as both a complementary and as a stand-alone procedure in facial rejuvenation.

Is immediate autologous breast reconstruction with postoperative radiotherapy good practice?: a systematic review of the literature

BACKGROUND

There remains controversy as to whether immediate autologous breast reconstruction with postoperative radiotherapy is associated with acceptable complications and aesthetic outcomes. This systematic review analyses the literature regarding outcomes of immediate autologous breast reconstruction with postoperative radiotherapy compared with no radiotherapy, as well as with delayed autologous breast reconstruction following post-mastectomy irradiation.

METHODS

Pubmed (1966 to October 2012), Ovid MEDLINE (1966 to October 2012), EMBASE (1980 to October 2012), and the Cochrane Database of Systematic Reviews (Issue 10, 2012) were searched. Overall complications (including fat necrosis), fat necrosis, revisional surgery, loss of volume, and aesthetic outcome, were analysed individually. Comparable data from observational studies were combined for meta-analysis where possible and quality assessment of the studies was performed.

RESULTS

The majority of studies of immediate autologous breast reconstruction and postoperative radiotherapy reported satisfactory outcomes (19 of 25 studies; n=1,247 patients). Meta-analysis of observational studies demonstrated no significant differences in total prevalence of complications (p=0.59) or revisional surgery (p=0.38) and a summary measure for fat necrosis favouring the group without radiotherapy (OR 2.82, 95% CI 1.35-5.92, p=0.006). The majority of studies comparing immediate reconstruction and postoperative radiotherapy with delayed reconstruction following post-mastectomy radiotherapy (10 of 12 observational studies; n=1,633 patients) reported satisfactory outcomes following immediate reconstruction. Meta-analysis of observational studies demonstrated no significant difference in overall incidence of complications (p=0.53) and fat necrosis (OR 0.63, 95% CI 0.29-1.38, p=0.25), and a summary measure for revisional surgery (OR 0.15, 95% CI 0.05-0.48, p=0.001) favouring the delayed surgery group. No randomised-controlled trials met the inclusion criteria, and all of the observational studies included were missing more than one important component for reporting of observational studies.

DISCUSSION

The majority of studies reported satisfactory outcomes and a similar incidence of complications for immediate autologous breast reconstruction and adjuvant radiotherapy when compared with no radiotherapy or delayed reconstruction following radiotherapy; the proportion that required revisional surgery was higher though for immediate than delayed breast reconstruction. The findings are limited by the paucity of high quality data in the published literature, and until better data is available the findings of this review suggest that immediate autologous breast reconstruction should at least be considered when adjuvant chest wall radiotherapy is anticipated.

Breast reconstruction with the denervated latissimus dorsi musculocutaneous flap

OBJECTIVE

To analyze clinical implications of the thoracodorsal nerve division in the latissimus dorsi musculocutaneous flap breast reconstruction.

PATIENTS AND METHODS

Prospective cohort study was conducted on 29 patients. Breast reconstruction with latissimus dorsi musculocutaneous flap was performed unilaterally in 20 patients or bilaterally in 9 women (38 breasts). Thoracodorsal nerve was divided during reconstruction of 20 breasts (group 1) and was preserved for 18 breasts (group 2). Height, width, projection, area of the covering skin and volume of the reconstructed and healthy breasts were measured on the 3D images of the anterior chest wall, taken 6 weeks and 6 months postoperatively with the Di3D 3D camera. Data regarding tissue consistency, painfulness and animation of the reconstructed breast, symmetry of both breasts and overall satisfaction after the surgery were collected at 6 months.

RESULTS

The reconstructed and healthy breasts decreased in volume in group 1 (-45.85 cm(3) ± 48.41 cm(3), p = 0.0004; -29.13 cm(3) ± 14.98 cm(3), p = 0.0009) and in group 2 (-31.5 cm(3) ± 25.35 cm(3), p = 0.0001; -15.4 cm(3) ± 21.96 cm(3), p = 0.0537). There were no differences in decrease in volume between groups 1 and 2 (p > 0.05). Respondents in group 1 in comparison to group 2 showed similar satisfaction of the tissue consistency of the reconstructed breast (p > 0.05) and the level of symmetry between both breasts (p > 0.05), gave lower scores for painfulness (p < 0.0001), animation (p < 0.0001) and higher scores for the overall satisfaction about the reconstructed breast (p = 0.0001).

CONCLUSION

We suggest that division of the thoracodorsal nerve during latissimus dorsi musculocutaneous flap breast reconstruction is a useful undertaking to minimize unnatural animation of the reconstructed breast.