Color Rendering in Medical Extended-Reality Applications

Cross-platform development of medical applications in extended-reality (XR) head-mounted displays (HMDs) often relies on game engines with rendering capabilities currently not standardized in the context of medical visualizations. Many aspects of the visualization pipeline including the characterization of color have yet to be consistently defined across rendering models and platforms. We examined the transfer of color properties from digital objects, through the rendering and image processing steps, to the RGB values sent to the display device. Five rendering pipeline configurations within the Unity engine were evaluated using 24 digital color patches. In the second experiment, the same configurations were evaluated with a tissue slide sample image. Measurements of the change in color associated with each configuration were characterized using the CIE 1976 color difference (ΔE). We found that the distribution of ΔE for the first experiment ranges from zero, as in the case using an Unlit Shader, to 25.97, as in the case using default configurations. The default Unity configuration consistently returned the highest ΔE across all 24 colors and also the largest range of color differences. In the second experiment, ΔEE ranged from 7.49 to 34.18. The Unlit configuration resulted in the highest ΔE in three of four selected pixels in the tissue sample image. Changes in color image properties associated with texture import settings were then evaluated in a third experiment using the TG18-QC test pattern. Differences in pixel values were found in all nine of the investigated texture import settings. The findings provide an initial characterization of color transfer and a basis for future work on standardization, consistency, and optimization of color in medical XR applications.     

A case of multiple schwannomas of the trigeminal nerves, acoustic nerves, lower cranial nerves, brachial plexuses and spinal canal: schwannomatosis or neurofibromatosis?

In most cases, while schwannoma is sporadically manifested as a single benign neoplasm, the presence of multiple schwannomas in one patient is usually indicative of neurofibromatosis 2. However, several recent reports have suggested that schwannomatosis itself may also be a distinct clinical entity. This study examines an extremely rare case of probable schwannomatosis associated with intracranial, intraspinal and peripheral involvements. A 63-year-old woman presented with a seven-year history of palpable lumps on both sides of the supraclavicular area and hearing impairment in both ears. On physical examination, no skin manifestations were evident. Facial sensory change, deafness in the left ear and decreased gag reflex were revealed by neurological examination. Magnetic resonance imaging revealed multiple lesions of the trigeminal nerves, acoustic nerves, lower cranial nerves, spinal accessory nerve, brachial plexuses, and spinal nerves. Pathological examination of tumors from the bilateral brachial plexuses, the spinal nerve in the T8 spinal position and the neck mass revealed benign schwannomas. Following is this patient case report of multiple schwannomas presenting with no skin manifestations of neurofibromatosis.     

Platelet adhesion onto segmented polyurethane film surfaces modified by addition and crosslinking of PEO-containing block copolymers

Polyethylene oxide (PEO) surfaces were prepared by the addition of PEO-containing amphiphilic block copolymers as surface modifying additives and of dicumyl peroxide (DCP) as a crosslinking agent in segmented polyurethane (PU). PEO-polypropylene oxide-PEO triblock copolymers (Pluronics) with different PEO chain length (from 0 to 98) were used as the surface modifying additives. The PEO additives in the PU film were then crosslinked to be stably entrapped in the PU matrix. The crosslinking was done by free radicals produced from the decomposition of DCP in the film through heating (120 degrees C) or ultraviolet irradiation (254 nm). The surface properties of the PEO additive-entrapped PU films were investigated by the measurement of water contact angles and electron spectroscopy for chemical analysis. The bulk properties such as water absorption, long-term film stability, and tensile strength and elongation at break, were also investigated. It was observed that addition of a small amount (5 wt% based on PU) of the PEO additives resulted in a considerable change of surface characteristics. The PEO additives were stably entrapped in the PU films by crosslinking of them, without significant changes of bulk properties of the films. From the platelet adhesion test on the prepared PEO additive-containing film surfaces, it was observed that the platelet adhesion on the surfaces decreases with increase in PEO chain length of PEO additives. The film surface containing additive with long PEO chains (chain length of 98) was particularly effective in preventing platelet adhesion. The crosslinking of the PEO additives in PU films did not affect the behavior of platelet adhesion on the surfaces; the films with crosslinked PEO additives showed similar platelet adhesion on the surfaces to the films with uncrosslinked ones.     

Nonvascular interventions of the urinary tract

Nonvascular intervention of the urinary tract is a well-established uroradiologic subspecialty, which is more important for avoiding invasive open surgery in the age of rising demand about the value of less invasive treatment. Various kinds of nonvascular intervention are recently performed under image-guidance and are as follows: percutaneous nephrostomy, percutaneous nephrostolithotomy, percutaneous dilatation of the urinary tract, sclerotherapy for renal cysts, percutaneous catheter drainage, percutaneous foreign body retrieval and biopsy. Percutaneous nephrostomy is a basic technique to provide a direct access to urinary tract, which makes it possible to perform other interventional procedures. Although nonvascular intervention may produce some complications, it is generally considered to be less invasive than open surgery and has advantages such as short hospital stay, early return to normal life and therefore economic savings. This review is described to help clinicians easily understand the procedures, indications, techniques, and complications with figures of cases the authors experienced.     

A case of Lambert-Eaton myasthenic syndrome associated with atypical bronchopulmonary carcinoid tumor

The Lambert-Eaton myasthenic syndrome (LEMS) is typically recognized as a paraneoplastic syndrome associated with a small cell lung carcinoma (SCLC), whereas LEMS with other neuroendocrine lung tumors, including carcinoids or large cell lung carcinoma, are highly unusual. Here, we report a rare case of LEMS with atypical bronchopulmonary carcinoid tumor: a 65-yr-old man presented with progressive leg weakness and a diagnosis of LEMS was made by serial repetitive nerve stimulation test. Chest CT revealed a lung nodule with enlargement of paratracheal lymph nodes, and surgically resected lesion showed pathological features of atypical carcinoid tumor. We concluded that LEMS could be associated with rare pulmonary neuroendocrine tumor other than SCLC, which necessitates pathologic confirmation followed by aggressive treatment for optimal management in these rare cases.     

Chemical, structural properties, and osteoconductive effectiveness of bone block derived from porcine cancellous bone

The purpose of this study is to determine the efficacy of bioactive calcium phosphate obtained from porcine cancellous bone for the treatment of bone defects and nonunion. Porcine cancellous bone blocks were heat treated at 1300 degrees C for 2 h. The chemical composition, calcium-to-phosphate ratio, and microstructure of the porcine bone blocks were examined. For in vivo implantation, bone defects were created on the anteromedial aspect of the proximal tibia in seven beagle dogs and the xenograft bone blocks were placed into these defects. Plain radiographs were taken at 2-week intervals for roentgenographic evaluation. At 12 weeks, the specimens were stained with hematoxylin and eosin (H&E). The composition and morphology of heat-treated porcine cancellous bone were found to be similar to heat-treated human cancellous bone. Radiographs showed union between the host bone/bone-block interfaces. At 12 weeks, uniform and substantial new bone formation was observed. It is concluded that heat-treated porcine cancellous bone demonstrated effective osteoconductivity. This high-temperature heat-treatment technique has several advantages, including decreased risk of disease transmission and immunoreactivity, while also offering excellent biocompatibility.     

Protein disulfide isomerase immunoreactivity and protein level changes in neurons and astrocytes in the gerbil hippocampal CA1 region following transient ischemia

We investigated the temporal and spatial alterations of protein disulfide isomerase (PDI) immunoreactivity and protein level in the hippocampus proper after 5 min transient forebrain ischemia in gerbils. PDI immunoreactivity was significantly altered in the hippocampal CA1 region. PDI immunoreactivity in the sham-operated animals was found in non-pyramidal cells. At 30 min after ischemia, PDI immunoreactivity was shown in the pyramidal cells of the stratum pyramidale (SP): the PDI immunoreactivity in the pyramidal cells was increased up to 12 h after ischemia. Thereafter PDI immunoreactivity was decreased, and the PDI immunoreactivity was shown in non-pyramidal cells 2 days after ischemia. Four to 5 days after ischemia, almost pyramidal cells in the CA1 region were lost because the delayed neuronal death occurred. At this time period, PDI immunoreactivity was expressed in some astrocytes as well as some neurons. The results of the Western blot analysis were consistent with the immunohistochemical data. These findings suggest that increase of PDI in pyramidal cells may play a critical role in resistance to ischemic damage at early time after ischemic insult, and that expression of this protein in astrocytes at late time after ischemic insult is partly implicated in the acquisition of tolerance against ischemic stress.     

DNA repair gene XRCC1 Arg399Gln polymorphism is associated with increased risk of uterine leiomyoma

BACKGROUND: DNA repair gene XRCC1 Arg399Gln polymorphism has been associated with the risk of several human tumours. In the present study we investigated whether the XRCC1 polymorphism is related to the risk of uterine leiomyoma, the most common neoplasm of the female genital tract. METHODS: Three hundred and twenty-seven patients with uterine leiomyoma and 197 normal controls were enrolled, and XRCC1 genotyping was determined by PCR and restriction fragment length polymorphism. RESULTS: The proportions of individuals homozygous for 399Arg allele, heterozygous and homozygous for the 399Gln allele were 85.8%, 13.7% and 0.5% among the control group, and 46.2%, 53.2% and 0.6% in those with leiomyoma (P < 0.001), respectively. Logistic regression analysis (after adjusting for age, parity, menarche age and body mass index) showed a significant increased risk of uterine leiomyoma in women with the Arg/Gln genotype versus the Arg/Arg genotype (odds ratio 6.79; 95% confidence interval 4.20-10.99; P < 0.001). CONCLUSIONS: In Korean women, the 399Gln polymorphism of XRCC1 is associated with an increased risk of uterine leiomyoma.     

Reversible Photo‐Mechanical Switching Behavior of Azobenzene‐Containing Semi‐Interpenetrating Network under UV and Visible Light Irradiation

Summary: Light‐induced reversible changes in elasticity of semi‐interpenetrating network (semi‐IPN) films bearing azobenzene moieties were achieved under both ultraviolet (UV) and visible light irradiation. The semi‐IPN film was prepared by a cationic copolymerization of azobenzene‐containing vinyl ethers in a linear polycarbonate (PC) film as a matrix. When the irradiation was switched on and off, the semi‐IPN film showed rapid reversible deformation with the same behavior occurring over a range of wavelengths, including both the UV and visible regions. The observed reversible deformation of the film was attributed to the decrease in the film's elasticity, which was assumed to be caused by the frequent trans‐cis cycling isomerization of azobenzene moieties taking place during the UV and visible light irradiation. This cycling makes it difficult for the azobenzene groups to aggregate, thus hindering their ability to function as pseudo‐crosslinking points.