Three-dimensional finite elemental analysis of zygomatic implants in craniofacial structures

The objective of this study was to analyse stress distribution in craniofacial structures around zygomatic osseointegrated implants. An integrated system for Digital Imaging and Communications in Medicine (DICOM) data were utilized to create a three-dimensional model of craniofacial structures. The amount and distribution of the main stresses were compared using three-dimensional finite elemental analysis. The system allowed visual confirmation and analysis of stress distribution as well as the convenient and simple construction of a digital biomechanical model that provided details of anatomical structures in the regions of interest. Zygomatic implants with or without connected implants supporting the superstructure were compared. Stresses in severely resorbed maxillae with connected implants were not concentrated around the alveolar bone supporting the zygomatic implants. Stresses where there were no connected implants tended to be generated in the zygomatic bone, at the middle part of the zygomatic implant and at the joint of the fixture-abutment. Stress due to occlusal forces is mainly supported by the zygomatic bone, is transferred predominantly through the infrazygomatic crest, and is divided between the frontal and temporal processes of the zygomatic bone in different directions.     

Development of Design Methods for a Centrifugal Blood Pump with a Fluid Dynamic Approach: Results in Hemolysis Tests

The purpose of this study was to examine the relationship between local flow conditions and the hemolysis level by integrating hemolysis tests, flow visualization, and computational fluid dynamics to establish practical design criteria for centrifugal blood pumps with lower levels of hemolysis. The Nikkiso centrifugal blood pump was used as a standard model, and pumps with different values of 3 geometrical parameters were tested. The studied parameters were the radial gap between the outer edge of the impeller vane and the casing wall, the position of the outlet port, and the discharge angle of the impeller vane. The effect of a narrow radial gap on hemolysis was consistent with no evidence that the outlet port position or the vane discharge angle affected blood trauma in so far as the Nikkiso centrifugal blood pump was concerned. The radial gap should be considered as a design parameter of a centrifugal blood pump to reduce blood trauma.     

A case of chordoid meningioma]

Chordoid meningioma is a very rare variant, especially in adults. We report an adult case of chordoid meningioma. A 52-year-old man was admitted to our hospital due to right hemiparesis. MRI revealed a left temporal convexity mass that showed two structures; the cerebral layer was shown as an isointensity area on T1WI and T2WI, and the dural layer seemed relatively hypointense on T1WI and hyperintense on T2WI. The tumor was well enhanced with gadolinium, especially on the dural side. A left external carotid arteriogram showed tumor stains with feeding vessels from the left middle meningeal artery. The tumor was totally removed via fronto-temporal craniotomy. Histological examination of the surgical specimen revealed two different structural components, meningothelial meningioma on the cerebral side, and chordoid meningioma on the dural side, consisting of clustering spindled cells and partly vacuolated ones in the mucoid stroma. In immunohistochemical examination, tumor cells showed positive staining for vimentin and epithelial membrane antigen (EMA), and negative for cytokeratin. From the above findings, this case was diagnosed as chordoid meningioma in an adult, a very rare variant of meningioma.     

Adaptation of guinea-pig superficial masseter muscle to an increase in occlusal vertical dimension.

To study the effect of increased occlusal vertical dimension on the fibre phenotypes of the superficial masseter muscle, the composition of myosin heavy-chains (MHC), myosin light-chains (MLC) and tropomyosin was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis in conjunction with densitometric analysis in normal (control) and bite-opened (5.7 mm increase in the vertical dimension for 1 week) guinea-pigs. The superficial masseter contained two fast-type MHC isoforms, II-1 and II-2, in both the bite-opened and control groups; their relative content (mean+/-SD, n = 7) was 47.8+/-2.9% and 52.2+/-2.9%, in the bite-opened and 44.4+/-3.0% and 55.6+3.0% in control preparations, indicating no significant (p>0.05) changes in MHC composition in association with the bite opening. On the other hand, significant differences in MLC and tropomyosin composition were found between the two preparations. Although the MLC consisted of three components, LC1f, LC2f and LC3f, in both preparations, their relative content (mean+/-SD, n = 7) was 37.1+/-2.4%, 49.6+/-1.6% and 13.2+/-3.2%, respectively, in the bite-opened and 28.1+/-3.1%, 50.9+/-1.6% and 21.0+/-3.5% in the control preparations, indicating that the bite opening induced a significant (p < 0.0001) increase in the relative content of LC1f at the expense of that of LC3f. Although the tropomyosin consisted of two components, TM-alpha and TM-beta, in both preparations, their relative content (mean+/-SD, n = 7) was 91.8%+/-1.9% and 8.2+/-1.9%, respectively, in the bite-opened and 95.9+/-0.7% and 4.1+/-0.7% in the control preparations, showing a significant (p < 0.001) increase in the relative content of TM-beta in relation to the bite opening. These results indicate that in guinea-pigs an increase in occlusal vertical dimension for 1 week changes the composition of MLC and tropomyosin, with no significant change in MHC, in the masseter muscle. These changes might be required to meet altered functional demands.     

T cell malignant lymphoma in the central nervous system after acute lymphoblastic leukemia in a child

A malignant lymphoma developed in the central nervous system (CNS) of a 7-year-old boy 5 years after he had received chemotherapy and cranial irradiation for acute lymphoblastic leukemia (ALL). Bone marrow analysis of the original leukemia showed a pre-B cell phenotype, whereas the resected brain tumor showed a T cell phenotype on immunophenotypic analysis. Because of this difference in immunophenotype, and because the patient had received multiple-drug chemotherapy and 1,800 cGy of cranial irradiation for the original ALL, we consider that the malignant lymphoma was a second neoplasm. This is a very rare case in two respects: it was a malignant lymphoma arising in the CNS as a second neoplasm after ALL and a T cell lymphoma occurring in a child. Received: 1 October 1998 Revised: 17 February 1999     

Post-voiding repeated renal ultrasonography for slight hydronephrosis detected during screening for asymptomatic microhematuria*

BACKGROUND: There is not a well established method for further screening of asymptomatic microhematuria found through annual health examinations. However, it is apparent that a large number of examiners are using ultrasonography for screening. When slight hydronephrosis is found through screening, it is difficult to determine whether further examinations, such as intravenous pyelography (IVP), should be performed. In this paper, we discuss the usefulness of post-voiding repeated renal ultrasonography, which was applied to 57 patients with slight hydronephrosis found in a screening. METHODS: Ultrasonography in the kidney and the urinary bladder at the ultrasound laboratory of Toma Hospital was carried out on a total of 1906 patients with asymptomatic microhematuria, which was found by routine annual health examination, from January 1996 to December 1998. Slight hydronephrosis was found in 57 (14 males and 43 females) of 1906 patients and post-voiding repeated renal ultrasonography was carried out on all patients. RESULTS: Slight hydronephrosis had disappeared and IVP was avoided in 22 (38.6%) of 57 patients. Of 35 cases in which slight hydronephrosis persisted after urination, there were no abnormalities on IVP in 32 patients, while abnormalities were found in three patients. Two of these had ureteropelvic junction stenosis and the remaining one had a ureteral stone. CONCLUSION: The results of this study indicate that post-voiding repeated renal ultrasonography is useful for avoiding unnecessary further examination to determine whether upper urinary tract obstruction exists, when slight hydronephrosis is observed upon screening by simultaneous renal and urinary bladder ultrasonography for asymptomatic microhematuria.     

Clinico-radiologic Characteristics of Pulmonary Visceral Larva Migrans Caused by Ascaris suum

Objective Visceral larva migrans (VLM) caused by Ascaris suum is a major health problem in pig farming regions. The clinical characteristics of pulmonary VLM caused by A. suum, however, are unclear. We assessed the clinico-radiologic features of this disease. Methods Medical records, including the results of chest radiography and high-resolution computed tomography (HRCT), were retrospectively reviewed from January 2000 through June 2019, at the University of Miyazaki Hospital and Kyoritsuiin Hospital in Miyazaki Prefecture, Japan. Results Seven patients with VLM caused by A. suum were identified. All seven patients had a unique habit of consuming raw foods, such as organic vegetables, chicken, turkey, wild boar, and venison. All but one patient, who had eosinophilic pneumonia with a fever and severe fatigue, had only mild or no respiratory symptoms. All 7 patients had remarkable eosinophilia (median, 1,960 /μL) and high serum IgE levels (median, 1,346 IU/mL). Chest HRCT revealed multiple nodules and multiple nodular ground-glass opacities in 57% and 29% of the patients, respectively. The pulmonary lesions were located predominantly in subpleural areas. All seven patients were treated with albendazole, which led to improvement within two to three months. Neither eggs nor parasites were detected in the feces or sputum of any patient. Conclusion Consumption of raw organic vegetables or raw meat is a possible route of A. suum infection. Infected patients exhibit mild respiratory symptoms, and multiple nodules with a halo in the subpleural area are a common finding on chest HRCT. Treatment with albendazole was effective in these cases.     

Surface Modification of Carbon Fiber-Polyetheretherketone Composite to Impart Bioactivity by Using Apatite Nuclei

The authors aimed to impart the apatite-forming ability to 50 wt% carbon fiber-polyetheretherketone composite (50C-PEEK), which has more suitable mechanical properties as artificial bone materials than pure PEEK. First, the 50C-PEEK was treated with sulfuric acid in a short time to form pores on the surface. Second, the surface of the 50C-PEEK was treated with oxygen plasma to improve the hydrophilicity. Finally, fine particles of calcium phosphate, which the authors refer to as “apatite nuclei”, were precipitated on the surface of the 50C-PEEK by soaking in an aqueous solution containing multiple inorganic ions such as phosphate and calcium (modified-SBF) at pH 8.20, 25 °C. The 50C-PEEK without the modified-SBF treatment did not show the formation of apatitic phase even after immersion in simulated body fluid (SBF) for 7 days. The 50C-PEEK treated with the modified-SBF showed the formation of apatitic phase on the entire surface within 1 day in the SBF. The apatite nuclei-precipitated 50C-PEEK will be expected as a new artificial bone material with high bioactivity that is obtained without complicated fabrication processes.     

Impact of Controlling a Nutritional Status Score on Wound Healing in Patients with Chronic Limb-Threatening Ischemia after Endovascular Treatment

Background: Chronic limb-threatening ischemia (CLTI) is the most advanced stage of peripheral artery disease. Therefore, a multidisciplinary approach is necessary to avoid major amputation in CLTI patients. Malnutrition worsens the condition of CLTI patients, and therefore, it may be important to evaluate the nutritional status in patients with CLTI. This study was designed to evaluate the baseline patient characteristics and the influence of the controlling nutritional status (CONUT) score on the clinical results. Method and Results: A retrospective, single-center, non-randomized study was conducted to evaluate the associations of death, major amputation, and wound healing rate at 12 months with the CONUT score on admission. Consecutive CLTI patients (mean age 73.2 ± 10.4 years; 84 males) who underwent endovascular therapy (EVT) for infra-popliteal lesions at Fukuoka University Hospital from January 2014 to May 2019 were enrolled and divided into two groups (higher and lower CONUT score groups). The higher CONUT group showed a higher percentage of dialysis (66.7% vs. 33.9%, p < 0.001) and a higher clinical frailty scale (5.9 ± 1.4 vs. 4.9 ± 1.9, p = 0.005) than the lower CONUT group. Rates of amputation-free survival were 89.5% and 69.8% in the lower and higher CONUT groups, respectively. In addition, rates of wound healing at 12 months were 98.0% and 78.3% in the lower and higher CONUT groups, respectively. Multivariate regression analysis demonstrated that a higher CONUT score was an independent predictor for delayed wound healing (OR: 11.2; 95% CI: 1.29–97.5; p = 0.028). Conclusion: An assessment of the nutritional status using the CONUT score could be useful for predicting wound healing, and earlier nutritional intervention may improve the outcome of CLTI patients. Early examination and treatment, along with raising awareness of the issue, may be important for improving the prognosis.