Lattice parameter changes of leucite by incorporation of various cations substituted for potassium

Leucite crystals having modified compositions from stoichiometry were prepared by the incorporation of Na+, Rb+, Cs+, Ca2+, Ba2+, and Sb3+ substituted for 5-50 at% of K+ in the leucite. The lattice parameters of the a- and c-axes of these tetragonal leucite were derived from the diffraction angles of (400) and (004) peaks due to tetragonal leucite, respectively. Both lattice parameters of the a- and c-axes of the leucites except Rb and Cs were slightly smaller than those of stoichiometric leucite. The lattice parameters of the a-axis of the leucites containing Rb and Cs were larger than those of stoichiometric leucite (p < 0.01) and increased with the content of Rb and Cs. It was concluded that the crystal lattice of leucite was deformed by the incorporation of cations substituted for K and their variations mainly depend upon the kind of cation, namely ionic size and substitution site in the lattice.

Severe diffuse atherosclerotic lesions of right gastroepiploic artery graft

The incidence of arteriosclerosis of the right gastroepiploic artery (RGEA) has not been widely known. We experienced one patient in whom the RGEA had severe diffuse atherosclerotic lesions and luminal narrowing, and was therefore determined to be unsuitable as a coronary bypass conduit at operation.

Physical evaluation of a system for direct digital intra-oral radiography based on a charge-coupled device

OBJECTIVES

To determine technical properties of a direct digital intra-oral radiographic system, the Dixel(R) (J Morita Corporation, Kyoto, Japan).

METHODS

A dose response function and the dark current were calculated from two series of exposures to a homogeneous radiation field. The line spread function (LSF) and the modulation transfer function (MTF) were determined from radiographs of an edge. The noise power spectrum (NPS) was determined at three exposures from radiographs exposed to homogeneous radiation fields. Noise equivalent quanta (NEQ) were calculated from the one-dimensional NPS and the MTF. The detective quantum efficiency (DQE) was determined from the NEQ and a representative value of the photon fluence. Signal-to-noise ratios (SNR) were calculated from the NEQs and different signal contrasts.

RESULTS

The dose response function demonstrated a slight curvature. There was no effect of the dark current. NPS ranged from 10-5 - 10-7 mm2 depending on exposure and frequency. At a peak of about 2 cycles/mm the DQE is on an average about 30 per cent. SNRs are favorable.

CONCLUSION

The technical properties found in this study indicate that the Dixel(R) system is suitable for intra-oral dental radiography.

Hydrothermal-electrochemical deposition of calcium phosphates on various metals

Calcium phosphates were formed on five kinds of substrate metals using a hydrothermal-electrochemical method in an autoclave with two electrodes. The electrolyte dissolving NaCl, K2HPO4, CaCl2.2H2O, tris (hydroxymethyl) aminomethane, and hydrochloric acid was maintained at 100 degrees C, 150 degrees C and 200 degrees C. The counter electrode, the anode, was platinum plate, 20 x 20 x 0.5 mm, and the working electrodes as cathode were pure titanium, pure zinc, pure nickel, pure iron, and stainless steel plates. A constant direct current at 12.5 mA/cm2 was loaded for 1 hr. Hydroxyapatite [Ca10(PO4)6(OH)2] only deposited at three temperatures on pure titanium plate. On pure zinc plate, both parascholzite [CaZn2(PO4)2.2H2O] and hydroxyapatite were formed at 150 degrees C and both parascholzite and ZnO were formed at 200 degrees C. Both hydroxyapatite and beta-TCP [beta-Ca3(PO4)2] were formed on pure nickel, pure iron, and stainless steel plates at 200 degrees C. It seems that the incorporation of the metal ions released from the electrode decreased the Ca/P ratio of the deposit due to the formation of other compounds except hydroxyapatite.

Prediction of perceptibility curves of direct digital intraoral radiographic systems

OBJECTIVES

To derive and test a method to predict Perceptibility Curves (PCs) for direct digital intraoral radiographic systems.

METHODS

A test object was used to determine the performance of an average observer with respect to the threshold contrast and internal noise of the human visual system. These data were combined with system parameters to predict PCs mathematically.

RESULTS

Data on the performance of an average observer could be defined to obtain values of the effective threshold contrast as a function of background gray level. This function combined with the gamma-value of the system predicted PCs that agreed well with PCs obtained in the conventional way.

CONCLUSION

It is possible to predict PCs from a limited number of system parameters together with predetermined data on an average observer.

Effect of cooling condition on leucite crystals in dental porcelains

X-ray diffractometry (XRD) was used to analyze the crystal phases of three commercial dentin and incisal porcelains prepared by normal cooling, quenching in water, and controlled slow annealing after normal firing. There were no remarkable differences in the contents of either tetragonal and cubic leucite in the fired porcelain discs prepared under the three cooling conditions. Furthermore, there were no significant differences in the parameters of the a-axis and c-axis of tetragonal leucite, and the a-axis of cubic leucite among them. These results suggest that the cooling condition has little effect on the microstructural changes of leucite crystals in the dental porcelains, since the leucite crystals were formed at a higher temperature range than the firing- and cooling-temperature range and were stabilized by incorporation of additives into the lattice.

Systemic granulomatous arteritis associated with Epstein-Barr virus infection

A 61-year-old woman initially presented with symptoms and findings reminiscent of infectious mononucleosis, and her illness then took a rapidly fatal course. Autopsy revealed widespread granulomatous arteritis, with multinucleated giant cells but without eosinophils and fibrinoid necrosis, affecting small arteries and arterioles and infiltration of haemophagocytic histiocytes into many organs. In situ hybridization with Epstein-Barr virus (EBV)-specific oligonucleotide probes showed positive signals in the infiltrating immune cells and epithelial and endothelial cells of the affected organs. EBV-associated haemophagocytic syndrome (EBV-AHS) with systemic granulomatous arteritis was diagnosed. From the immunophenotypes of the infiltrating immune cells, a possible role of CD4+ T-cells in the pathogenesis of this haemophagocytic syndrome and granulomatous vasculitis was suggested.

Retroperitoneal malignant mesenchymoma: imaging findings in five cases

BACKGROUND

To describe computed tomographic (CT), magnetic resonance (MR), ultrasonographic (US), and angiographic findings of retroperitoneal malignant mesenchymoma with emphasis on CT findings.

METHODS

Five CT, four US, four angiography, and two MR studies were obtained in five patients with pathologically proven retroperitoneal malignant mesenchymoma.

RESULTS

Tumors were larger than 10 cm (n = 4), well-circumscribed and heterogeneous (n = 4), and with massive intratumorous calcifications (n = 3) on plain CT or US. Tumors showed heterogeneous enhancement on contrast-enhanced CT scans (n = 4) and moderate hypervascularity with heterogeneous staining on angiography (n = 3). Tumors were essentially hypointense on T1-weighted MR images (n = 2) and heterogeneous hyperintense on T2-weighted MR images (n = 2). Plain CT showed a fat-dense structure in a tumor in one patient.

CONCLUSIONS

The radiologic findings of large expansile heterogeneous masses in the retroperitoneum, especially with massive calcifications, were considered to be typical of malignant mesenchymomas.

Hydrothermal-electrochemical deposition of hydroxyapatite

Hydroxyapatite crystals were formed on a titanium electrode using the hydrothermal-electrochemical method in an autoclave with two electrodes. The electrolyte dissolving NaCl, K2HPO4, CaCl2.2H2O, trishydroxyaminomethane, and hydrochloric acid was maintained at 80 degrees - 200 degrees C. After loading of a constant current at 12.5 mA/cm2 for 1 h, the deposited amounts were measured through the weight gain of the electrode. The deposits were characterized by X-ray diffractometry, Fourier transform infrared spectroscopy, field emission-type scanning electron microscopy, field emission-type transmission electron microscopy, and energy dispersive X-ray spectroscopy. The deposited amount increased with electrolyte temperatures up to 150 degrees C and slightly decreased above that temperature. The deposits were identified as hydroxyapatite crystal rods grown along the c axis and perpendicular to the substrate. The crystallinity of the deposited hydroxyapatite increased continuously with the electrolyte temperature and closed to stoichiometric hydroxyapatite. At 150 degrees - 160 degrees C, the hydroxyapatite rod grew very homogeneously perpendicular to the substrate, and the edge of the needle had a flat hexagonal plane.

Microstructure and homogeneity of dental porcelain frits

The microstructure and homogeneity of three commercial dentin and incisal unfired porcelain frits (one conventional and two ultra-low fusing types, fused-to metal were analyzed by X-ray diffractometry, scanning electron microspectroscopy, and wavelength- and energy dispersive X-ray microspectroscopy. The average contents of tetragonal and cubic leucite for the conventional and one of the ultra-low fusing type frits were 20.1-22.6 wt% and 0-2.6 wt%, respectively, whereas those of another of the ultra-low fusing type frits were about 11.5-11.6 wt% and 2.9-4.6 wt%, respectively. The conventional type frits seemed to be admixtures of three kinds of glass frits. One of the ultra-low fusing type frits seemed to be an admixture of four kinds of glass frits. Another ultra-low fusing frits seemed to be only one kind of glass frit dispersed with small size, less than 1 micron, leucite crystals. There were no remarkable differences in microstructure and homogeneity between dentin and incisal porcelain frits in each brand.

Sonographic analysis of recurrent parotitis in children: a comparative study with sialographic findings

OBJECTIVE

The sonographic features of recurrent parotitis in children were studied to clarify a relationship between sonographic and sialographic findings in this disease.

STUDY DESIGN

Twenty-one glands (7 on follow-up) were examined by 7.5 MHz ultrasonography and sialography. Echo intensity level, distribution of the internal echoes, and size of hypoechoic areas were compared with the size of punctate shadows on the sialograms. Twenty other histopathologic specimens were analyzed to investigate the entity of hypoechoic areas.

RESULTS

Sonography showed hypoechoic, heterogeneous internal echoes, the level of which increased as the punctate shadows enlarged. Hypoechoic areas, all of which were larger than the sialographic punctate shadows, were observed in 62% of the glands. Histopathologic analysis suggests that these hypoechoic areas represent dilated peripheral ducts with lymphocytic infiltration. Sonography was likely to detect changes over time more sensitively than sialography.

CONCLUSIONS

Sonography should be performed as the test of first choice, both in the primary and follow-up stages, in cases of recurrent parotitis in children.

Imprint cytology of large B-cell lymphoma with high content of epithelioid cells. A report of two cases

An association of epithelioid cell reaction in follicular center cell lymphomas seems to be a rare phenomenon. The cytological features of this type of B-cell lymphoma from two patients are presented. In both cases, immunohistochemistry applied to paraffin sections revealed reactivity of tumor cells for CD10, 20 and 79a. The first patient, a 77-year-old male, presented with bilateral inguinal bulky masses. The second patient, a 76-year-old female, revealed left supraclavicular bulky masses. Imprint cytological specimens of these two cases showed large lymphoid cells interspersed with epithelioid histiocytes, which were present in small aggregated clusters or in isolated forms. Most tumor cells showed centroblastic morphology, whereas the minority of them looked like immunoblasts. Occasionally, a monotonous proliferation of these large atypical blastic cells was also detected. On the other hand, in some parts of the imprint specimens, numerous epithelioid cells obscured the underlining tumor cells. Reactive cells other than epithelioid cells were not prominent. These cytologic features closely resembled the histologic patterns of this rare follicular center cell lymphoma. Careful examination of the cytological specimens is needed to detect the monotonous proliferation of tumor cells to establish the diagnosis of malignant lymphoma.

Late cyst convolution after gamma knife radiosurgery for cerebral arteriovenous malformations

Although many series of patients with cerebral arteriovenous malformations (AVMs) treated radiosurgically have been published, there has been little information on cysts appearing several years after irradiation. Herein, we discuss the incidence, mechanisms and predictability of late cyst formation based on our personal experiences, as well as reported patients. The incidence of this complication, though generally considered to be 0.5% or less, may be higher than assumed. Although a breakdown of the blood-brain barrier is likely to play a major role in the formation process, the hematoma cavity itself may have the potential to become a cyst. A radiation-induced lesion appearing several years after irradiation and persisting for several years thereafter may be a warning sign of late cyst formation. Long-term follow-up, particularly using neuroimaging techniques, is necessary even after the 'treatment goal' has been achieved.

Usefulness of the high-frequency ultrasound probe in pretherapeutic staging of superficial-type colorectal tumors

We evaluated the usefulness of the high-frequency ultrasound probe (HFUP, 20 MHz) to determine the depth of tumor invasion in 45 patients with superficial colorectal tumors. The correct diagnostic rate was 66% (30/45) when the depth of tumor invasion was classified into the following 6 layers: mucosa (m), upper 1/3 (sm1), middle 1/3 (sm2), and lower 1/3 (sm3) areas of the submucosa, muscularis propria (mp), and the subserosa or deeper areas (s). However, when the depth of tumor invasion was evaluated in 3 layers (m-sm1, sm2-sm3, and mp-deeper layer), which is the classification used to select cases for endoscopic mucosal resection, the correct diagnostic rate was 88.9% (40/45). These results suggest that the HFUP is useful to determine the depth of invasion to select treatment for superficial colorectal tumors.

Florid reactive follicular hyperplasia in elderly patients. A clinicopathological study of 23 cases

Florid reactive follicular hyperplasia (FRFH) of the enlarged lymph node in elderly patients requiring biopsy is a relatively uncommon phenomenon as compared with younger age groups. We experienced 23 patients, aged 60 years or more, from whom the biopsied lymph node specimens histologically showed inappropriate FRFH for their age, in the period between 1982 and 1996. These cases were morphologically subdivided into three groups, FRFH with interfollicular plasmacytosis, that with progressive transformation of germinal center, and FRFH without additional specific findings. FRFH with interfollicular plasmacytosis were observed in 11 cases, all of whom were accompanied with several immunological abnormalities (six with rheumatoid arthritis, three with multicentric Castleman's disease and one each with myoepithelial sialoadenitis and autoimmune hemolytic anemia). Three men with uncertain etiology exhibited an unusual histology of progressive transformed germinal centers which were clinically characterized by a bulky neck mass. Among the nine cases with nonspecific FRFH, only four had a specific etiology (one each with adult onset Still's disease, chronic sinusitis, Epstein-Barr virus infection and infectious lateral cervical cyst), while the other five with unknown etiology showed abnormal laboratory findings suggestive of an abnormal humoral immune response, i.e. hypergammaglobulinemia and seropositivities for some autoantibodies. None of our patients developed malignant lymphoma during the follow-up period. Of note, 16 (70%) of the 23 cases were found to be associated with various types of imbalances of the immune system, some of which appeared to be currently ill-defined as clinicopathological entities that were simply categorized as autoimmune disease.

Laparoscopic inguinal hernia repair using fine-caliber instruments and polyester mesh

Laparoscopic inguinal hernia repair (LH) requires similar scar size to traditional open repair. To perform LH with minimal access, finer instruments were used. A 5-mm laparoscope was inserted from the umbilicus, and surgical instruments were inserted through 5- and 3-mm trocars to perform LH by the transabdominal preperitoneal approach. Polyester mesh was placed over the hernia orifice and the peritoneum was closed with 3-0 silk sutures. Sixteen patients underwent smaller access LH and 24 had standard LH. Although smaller access LH took longer (105.7 versus 83.9 min), significantly fewer patients required analgesia after smaller access LH than after standard LH (12.5 versus 70.8%), and the postoperative hospital stay was shorter (4.6 versus 5.6 days). In addition, a better cosmetic outcome was obtained with smaller access LH. In conclusion, access was minimized by using fine-caliber instruments and polyester mesh, making LH less invasive and improving the cosmetic outcome.

Morphology and microstructure of electrochemically deposited calcium phosphates in a modified simulated body fluid

Calcium phosphates were deposited on a pure titanium plate for various loading times under 1.3 and 12.9 mA/cm2 in a modified simulated body fluid at 52-92 degrees C. The plate-like crystals formed under 1.3 mA/cm2 were identified to be octacalcium phosphate (OCP) and/or carbonate-containing apatite. OCP converted to carbonate-containing apatite with the elapsing time of the loading current. The needle-like precipitates formed under 12.9 mA/cm2 were identified to be carbonate-containing apatite crystals elongated parallel to the c-axis direction. The degrees of crystallinity of the deposits formed under 1.3 mA/cm2 showed the highest value around 72 degrees C, whereas those under 12.9 mA/cm2 increased with the electrolyte temperature. The carbonate content of the deposits decreased with the electrolyte temperature and the flow current. The degree of crystallinity of the electrochemically deposited calcium phosphates decreased with the carbonate content.

Local recurrence of early esophageal carcinoma after endoscopic mucosal resection

We performed endoscopic mucosal resection on 25 patients with early esophageal carcinoma where the depth of invasion was limited to in the lamina propria mucosae (m2) and we observed local recurrent cancer in 2 patients (8%). To reduce the rate of local recurrent cancer, the method of resection was aimed at pathological negative stumps and establishment of a strict standard of judgement on clinically complete resection were considered to be necessary. Furthermore, complete cure was possible even in patients with pathologically positive stumps in cases where no recurrent cancer was observed over a 1 year period following endoscopic mucosal resection.

Iodine staining for early endoscopic detection of esophageal cancer in alcoholics

BACKGROUND AND STUDY AIMS

A retrospective epidemiological investigation has demonstrated that alcohol abuse is a major risk factor for esophageal cancer. However, prospective endoscopic screening for early detection in heavy drinkers is not available at present.

PATIENTS AND METHODS

A prospective study was conducted that included 255 alcoholics (aged 52 +/- 9 years). The patients were consecutively screened using esophagoscopy with iodine staining and targeted biopsy. The study also explored whether there was a relationship between the amount of alcohol intake and the detection rate of esophageal cancer.

RESULTS

Unstained lesions (larger than 5 mm) were observed on the esophageal wall in 55 patients (21.6%). Ten patients (3.9%) with 13 lesions were found to have esophageal cancer of the superficial type, with no symptoms. Cancer invasion was confined to the epithelium in three patients, to the lamina propria in seven, and to the submucosa in three. There was a direct relationship between substantial alcohol intake and the presence of esophageal cancer.

CONCLUSION

Screening esophagoscopy with iodine staining is very advantageous in detecting esophageal cancer at an early stage.

Systemic lupus erythematosus (SLE) lymphadenopathy presenting with histopathologic features of Castleman' disease: a clinicopathologic study of five cases

Lymph node enlargement is common in active systemic lupus erythematosus (SLE), a disease characterized by well defined clinical criteria. Although numerous reports have described the characteristic histology of SLE lymphadenopathy to include necrotizing lesions and hematoxylin bodies, no detailed description has examined the histopathologic features that are similar to Castleman's disease (CD) in SLE patients. In this report, we describe the clinicopathologic findings of CD-like peripheral lymphadenopathy, which was identified in five (26%) of 19 SLE patients. These five patients were all female with an age range of 24 to 44 years, and four of them presented with multicentric lymphadenopathy. They also had systemic symptoms and abnormal laboratory findings, indicating active disease, although two patients had not fulfilled the diagnostic criteria of SLE at the initial disease. The size of the enlarged lymph nodes seldom exceeded 2.0 cm in diameter, and biopsies revealed histopathologic features similar to CD, of intermediate type in three patients and hyaline vascular type in two according to the classification of Flendrig [7]. Immunohistochemical studies demonstrated polyclonal plasma cell populations in all five cases. Epstein-Barr virus genomes were detected in the small lymphocytes of two of the three cases examined by in situ hybridization studies. Recently, the histopathologic findings of CD have been associated with a disrupted immune response, and the present data suggest that SLE should be listed as one of the diseases showing the histopathologic features similar to CD.

Glass transition temperatures of dental porcelains determined by DSC measurement

The differential scanning calorimetry (DSC) curves for three commercial dentin and incisal porcelains fused-to metal were measured using high-temperature DSC. The glass transition temperatures (Tg) were determined from the DSC curves at heating rates of 7-20 degrees C/min, and the activation energy was derived from an Arrhenius plot of negative reciprocal Tg vs. logarithm of heating rate. The Tg of the dental porcelains depended on the content of aluminum oxide, whereas the activation energy depended on the content of sodium oxide. The ultra-low fusing type porcelains had a low activation energy due to the higher content of sodium oxide than the other porcelains.

A diffuse white matter ischemic lesion appearing 7 years after stereotactic radiosurgery for cerebral arteriovenous malformations: case report

OBJECTIVE AND IMPORTANCE

Little information is available about radiation-induced complications occurring more than 5 years after radiosurgical treatment for arteriovenous malformations.

CLINICAL PRESENTATION

We present a patient with arteriovenous malformations who experienced hemimotor weakness caused by a diffuse white matter necrotic lesion developing 7 years after gamma knife radiosurgery. The original nidus had been too large (24.1 cm3) to be totally covered and irradiated with a peripheral dose of 20 to 25 Gy. Therefore, the lower half of the nidus, which was adjacent to the major feeding artery, had been partially covered with a 30% isodose volume using two target points with an 18-mm collimator. A central dose of 70 Gy was used to obtain 21 Gy at the periphery. Complete nidus obliteration was angiographically confirmed 38 months after radiosurgery. After a 6-year uncomplicated period, this patient experienced a convulsive seizure and then mild right hemiparesis.

INTERVENTION

Computed tomography demonstrated a diffuse hypodense area in the left white matter, which had not been revealed by the previous examination. With steroid treatment, this patient achieved clinical improvement, although there was no significant improvement in the computed tomography-demonstrated white matter lesion.

CONCLUSION

Although the evaluation of this patient may not be sufficient and further examinations may be necessary, we tentatively conclude that the computed tomography-demonstrated hypodense lesion in this patient is a radiation-related necrotic lesion. Long-term follow-up is crucial, even after the "treatment goal" has been achieved.