Tracking errors related to cardiac cycle: a new approach

One-dimensional manual tracking was investigated in relation to cardiac activity. The task of the subjects was, by means of a joy-stick, to maintain a spotlight between two vertical lines moving horizontally across an oscilloscope screen. Error incidence was time-locked with respect to the cardiac cycle. Error rate was higher for faster (2-s trial periods) than for slower (3-s trial periods) target movement. Using linear-ramp and sinusoidal movements, it was demonstrated that error incidence is associated with positive and negative cardiac acceleration.     

Familial amyloidotic polyneuropathy: long-term follow-up of abdominal fat tissue aspirate in patients with and without liver transplantation.

To estimate the evolution of amyloid in tissue, we studied abdominal fat aspirates of cases with familial amyloidotic polyneuropathy (FAP) longitudinally at regular intervals between 1994 and 2006. In 22 cases (13 carriers and nine patients) not yet transplanted median follow-up was 3.3 years (range 0.4-11.3). We found a significant increase in the amyloid grade of fat tissue from 2+ to 4+ and from 0 to 4+ in two of three subjects with follow-ups of >7 years, after 7 and 11 years, respectively. All other subjects remained negative or did not show a significant change. In 11 liver transplant patients, follow-up with fat aspirate was available with a median duration of 3.1 years (range 1.0-10.1). A comparison was made with cardiac amyloid as judged by the cardiac septum diameter and the serum NT-ProBNP (N-terminal pro-B-type natriuretic peptide) level. No stable increase of amyloid in fat was seen in any patient. A stable decrease of amyloid grade was seen in one patient 5 years after transplantation. In contrast, the cardiac septum diameter increased >or=4 mm in six of the 11 transplant patients. Our study shows the diagnostic utility of a regularly repeated fat aspirate in carriers at risk for the development of ATTR amyloidosis. Evolution of amyloid deposition in fat tissue is very gradual. After liver transplantation, amyloid deposition in fat tissue seems to stabilize and may even decrease in the long term, whereas amyloid deposition in cardiac tissue appears to be progressive.     

Comparison of inhomogeneity correction algorithms in small photon fields

Algorithms such as convolution superposition, Batho, and equivalent pathlength which were originally developed and validated for conventional treatments under conditions of electronic equilibrium using relatively large fields greater than 5 x 5 cm2 are routinely employed for inhomogeneity corrections. Modern day treatments using intensity modulated radiation therapy employ small beamlets characterized by the resolution of the multileaf collimator. These beamlets, in general, do not provide electronic equilibrium even in a homogeneous medium, and these effects are exaggerated in media with inhomogenieties. Monte Carlo simulations are becoming a tool of choice in understanding the dosimetry of small photon fields as they encounter low density media. In this study, depth dose data from the Monte Carlo simulations are compared to the results of the convolution superposition, Batho, and equivalent pathlength algorithms. The central axis dose within the low-density inhomogeneity as calculated by Monte Carlo simulation and convolution superposition decreases for small field sizes whereas it increases using the Batho and equivalent pathlength algorithms. The dose perturbation factor (DPF) is defined as the ratio of dose to a point within the inhomogeneity to the same point in a homogeneous phantom. The dose correction factor is defined as the ratio of dose calculated by an algorithm at a point to the Monte Carlo derived dose at the same point, respectively. DPF is noted to be significant for small fields and low density for all algorithms. Comparisons of the algorithms with Monte Carlo simulations is reflected in the DCF, which is close to 1.0 for the convolution-superposition algorithm. The Batho and equivalent pathlength algorithms differ significantly from Monte Carlo simulation for most field sizes and densities. Convolution superposition shows better agreement with Monte Carlo data versus the Batho or equivalent pathlength corrections. As the field size increases the DCF's for all algorithms converge toward 1.0. The largest differences in DCF are at the interface where changes in electron transport are greatest. For a 6 MV photon beam, electronic equilibrium is restored at field sizes above 3 cm diameter and all of the algorithms predict dose in and beyond the inhomogeneous region equally well. For accurate dosimetry of small fields within and near inhomogeneities, however, simple algorithms such as Batho and equivalent pathlength should be avoided.     

Visual perception: double pulse temporal resolution. (Lack of contingency upon the phase of resting cardiac and respiratory cycle)

Double light pulse resolution required longer inter-pulse time intervals of short duration of the pulse. The threshold of double pulse discrimination was not contingent upon the actual phase of cardiac or respiratory cycle.     

Residues involved in the antigenic sites of transmissible gastroenteritis coronavirus S glycoprotein.

The S glycoprotein of transmissible gastroenteritis virus (TGEV) has been shown to contain four major antigenic sites (A, B, C, and D). Site A is the main inducer of neutralizing antibodies and has been previously subdivided into the three subsites Aa, Ab, and Ac. The residues that contribute to these sites were localized by sequence analysis of 21 mutants that escaped neutralization or binding by TGEV-specific monoclonal antibodies (MAbs), and by epitope scanning (PEPSCAN). Site A contains the residues 538, 591, and 543, which are essential in the formation of subsites Aa, Ab, and Ac, respectively. In addition, mar mutant 1B.H6 with residue 586 changed had partially altered both subsite Aa and Ab, indicating that these subsites overlap in residue 586; i.e. this residue also is part of site A. The peptide 537-MKSGYGQPIA-547 represents, at least partially, subsite Ac which is highly conserved among coronaviruses. This site is relevant for diagnosis and could be of interest for protection. Other residues contribute to site B (residues 97 and 144), site C (residues 50 and 51), and site D (residue 385). The location of site D is in agreement with PEPSCAN results. Site C can be represented by the peptide 48-P-P/S-N-S-D/E-52 but is not exposed on the surface of native virus. Its accessibility can be modulated by treatment at pH greater than 11 (at 4 degrees) and temperatures greater than 45 degrees. Sites A and B are fully dependent on glycosylation for proper folding, while sites C and D are fully or partially independent of glycosylation, respectively. Once the S glycoprotein has been assembled into the virion, the carbohydrate moiety is not essential for the antigenic sites.     

Daily CT localization for correcting portal errors in the treatment of prostate cancer

Introduction: Improved prostate localization techniques should allow the reduction of margins around the target to facilitate dose escalation in high-risk patients while minimizing the risk of normal tissue morbidity. A daily CT simulation technique is presented to assess setup variations in portal placement and organ motion for the treatment of localized prostate cancer.

Methods and Materials: Six patients who consented to this study underwent supine position CT simulation with an alpha cradle cast, intravenous contrast, and urethrogram. Patients received 46 Gy to the initial Planning Treatment Volume (PTV₁) in a four-field conformal technique that included the prostate, seminal vesicles, and lymph nodes as the Gross Tumor Volume (GTV₁). The prostate or prostate and seminal vesicles (GTV₂) then received 56 Gy to PTV₂. All doses were delivered in 2-Gy fractions.

After 5 weeks of treatment (50 Gy), a second CT simulation was performed. The alpha cradle was secured to a specially designed rigid sliding board. The prostate was contoured and a new isocenter was generated with appropriate surface markers. Prostate-only treatment portals for the final conedown (GTV₃) were created with a 0.25-cm margin from the GTV to PTV. On each subsequent treatment day, the patient was placed in his cast on the sliding board for a repeat CT simulation. The daily isocenter was recalculated in the anterior/posterior (A/P) and lateral dimension and compared to the 50-Gy CT simulation isocenter. Couch and surface marker shifts were calculated to produce portal alignment. To maintain proper positioning, the patients were transferred to a stretcher while on the sliding board in the cast and transported to the treatment room where they were then transferred to the treatment couch. The patients were then treated to the corrected isocenter. Portal films and electronic portal images were obtained for each field.

Results: Utilizing CT–CT image registration (fusion) of the daily and 50-Gy baseline CT scans, the isocenter changes were quantified to reflect the contribution of positional (surface marker shifts) error and absolute prostate motion relative to the bony pelvis. The maximum daily A/P shift was 7.3 mm. Motion was less than 5 mm in the remaining patients and the overall mean magnitude change was 2.9 mm. The overall variability was quantified by a pooled standard deviation of 1.7 mm. The maximum lateral shifts were less than 3 mm for all patients. With careful attention to patient positioning, maximal portal placement error was reduced to 3 mm.

Conclusion: In our experience, prostate motion after 50 Gy was significantly less than previously reported. This may reflect early physiologic changes due to radiation, which restrict prostate motion. This observation is being tested in a separate study. Intrapatient and overall population variance was minimal. With daily isocenter correction of setup and organ motion errors by CT imaging, PTV margins can be significantly reduced or eliminated. We believe this will facilitate further dose escalation in high-risk patients with minimal risk of increased morbidity. This technique may also be beneficial in low-risk patients by sparing more normal surrounding tissue.     

Extensively drug-resistant (XDR) Neisseria gonorrhoeae causing possible gonorrhoea treatment failure with ceftriaxone plus azithromycin in Austria,April 2022

We describe a gonorrhoea case with ceftriaxone plus high-level azithromycin resistance. In April 2022, an Austrian heterosexual male was diagnosed with gonorrhoea after sexual intercourse with a female sex worker in Cambodia. Recommended treatment with ceftriaxone (1 g) plus azithromycin (1.5 g) possibly failed. Worryingly, this is the second strain in an Asian Neisseria gonorrhoeae genomic sublineage including high-level azithromycin-resistant strains that developed ceftriaxone resistance by acquisition of mosaic penA-60.001. Enhanced resistance surveillance and actions are imperative to prevent spread.     

Insights on Skin Quality and Clinical Practice Trends in Asia Pacific and a Practical Guide to Good Skin Quality from the Inside Out

ObjectiveWe sought to examine the current skin quality trends and gaps in clinical practice in the Asia Pacific region and develop a practical guide to improve skin quality.MethodsMedical practitioners from 11 countries in the Asia Pacific region completed an online survey on current trends in skin quality treatment. A panel of 12 leading experts convened for a virtual meeting to develop a practical guide for skin quality improvement.ResultsA total of 153 practitioners completed the survey. The four most common skin quality issues were uneven skin tone, skin surface unevenness, skin laxity, and sebaceous gland hyperactivity and enlarged pores. Most practitioners reported using a combination of treatment modalities for each skin quality issue. It was also observed that each treatment modality could be used to treat several skin quality issues. A multimodal approach targeting different interrelated issues across the tissue planes was recommended for balanced results. The panel developed a practical guide for the appropriate combinations and sequence of treatments, and created treatment protocols for specific skin quality outcome goals. The guide employed an “inside-out” approach, treating the deeper tissue planes prior to the superficial layers to achieve harmonious results.LimitationsFuture studies are needed to support the recommended treatment protocols for skin quality improvement.ConclusionThese findings provide valuable insights on current skin quality trends and gaps in clinical practice. The practical guide provides a framework for practitioners to customize their treatment plan according to each patient’s needs.     

Density and morphology of corneal endothelial cell after phacoemulsification using ringer lactate versus balanced salt solution as irrigating solutions

AIM: To compare the difference in corneal endothelial cell density and morphology after phacoemulsification using ringer lactate (RL) and balanced salt solution (BSS) irrigating solutions. METHODS: The prospective randomized controlled trial study was conducted between February 2017 and April 2017 in Dr. YAP Eye Hospital, Yogyakarta, Indonesia. There were a total of 52 subjects (52 eyes) who were senile cataract patients further grouped into two, 26 patients undergoing the phacoemulsification procedure using RL irrigating solution and the other 26 patients with BSS irrigating solution, both conducted by one operator. On the 1, 7, and 28d post operative, an evaluation was done to measure the density and corneal endothelial cell morphology, as well as the variable of inflammation in the two groups. RESULTS: Fifty-two eyes had undergone phacoemulsification with posterior intraocular lens implantation. Both groups were evaluated for the endothelial cell reduction and corneal endothelial cell morphology change, along with postoperative inflammation. On the 28d postoperative, endothelial cell reduction in the BSS group (173.96 cell/mm2, 8.12%) was lower than the RL group (253.20 cell/mm2, 10.25%), percentage of corneal endothelial cell variation coefficient increase in the BSS group (2.92%, 8.36%) was lower compared to the RL group (3.42%, 9.96%), decrease of hexagonal cells of corneal endothelium cells presentation percentage in the BSS group (4.30%, 8.17%) was lower compared to the RL group (4.84%, 8.97%), and the percentage increase of central corneal thickness in the BSS group (4.69 μm, 0.89%) was almost equal to the RL group (4.53 μm, 0.90%). All of the results regarding difference in density and corneal cell endothelium morphology between the two groups did not reveal any statistically significant difference (P>0.05). Inflammatory variable in the two groups were even. CONCLUSION: BSS and RL were equal in their capability of maintaining endothelial cell loss and endothelial cell morphologic change in senile cataract patients after phacoemulsification.