Correlation Between Contrast-Detail Analysis and Clinical Image Quality Assessment of Intrapulmonary Lesions in Dual-Energy Subtraction Chest Radiography Using the Two-Shot Method: A Phantom Study

RATIONALE AND OBJECTIVES

Dual-energy subtraction (DES) imaging constitutes a technique that has demonstrated efficacy in enhancing the detectability of pulmonary nodules on chest radiographs. However, a simple and quantitative methodology for evaluating the clinical image quality of DES images is currently lacking. The objective of this study was to investigate the applicability of contrast-detail (C-D) phantom analysis to the visual clinical image quality evaluation of chest DES images.

MATERIALS AND METHODS

We employed a custom-made phantom incorporating the C-D phantom and a multipurpose anthropomorphic adult chest phantom. Two phantom sizes were utilized to simulate standard- and large-bodied adult patients for each phantom. The custom-made phantom images were scored automatically using dedicated software, yielding an inverse image quality figure (IQFinv) value. The multipurpose anthropomorphic adult chest phantom was employed in a visual grading analysis (VGA) study that was conducted by two experienced radiologists and five radiological technologists. Each nodule placed in the chest phantom image was rated on a 4-point Likert scale.

RESULTS

A statistically significant correlation was observed between the VGA scores of the seven observers and the obtained IQFinv values.

CONCLUSION

The findings of this study suggest that DES image analysis of the C-D phantom possesses the potential to be utilized for the evaluation of clinical DES image quality based on chest lesion detectability.

[Dosimetric Properties of Brass Mesh Bolus for High-energy Photon Beam]

PURPOSE

To investigate fundamental dosimetric properties of surface dose, exit dose, and beam profile of the brass mesh bolus for 4, 6, and 10 MV high-energy photon beams in radiation therapy.

METHODS

Surface dose and exit dose in the water-equivalent phantom were measured, and percent depth doses (PDDs) were calculated with no bolus, one layer of brass mesh, two layers of brass mesh bolus, three layers of brass mesh bolus, and 0.5 cm tissue-equivalent (TE) bolus. Exit dose was measured at a phantom thickness of 10 cm. Beam profiles were measured at phantom depths of 0 cm and 10 cm. All dosimetry was performed for 4, 6, and 10 MV photon beams using a linear accelerator.

RESULTS

The surface dose at a phantom depth of 0 cm increased to 37.3%, 36.3%, and 31.0% for 4, 6, and 10 MV, respectively, with the brass mesh bolus compared to the case of no bolus. The surface dose decreased with one layer of brass mesh bolus compared to that with the 0.5 cm TE bolus. On the other hand, the exit dose increased to 22.0%, 23.1%, and 22.8% for 4, 6, and 10 MV, respectively, with the brass mesh bolus compared to the case of no bolus. The beam profile at the depth of 0 cm showed oscillations, and the difference between the maximum and minimum doses was up to 13.1% with one layer of brass mesh bolus.

CONCLUSION

It was suggested that the brass mesh bolus not only increases the surface dose but also has different properties from the conventional TE bolus.

Effect of high- and low-energy entrance surface dose allocation ratio for two-shot dual-energy subtraction imaging on low-contrast resolution

INTRODUCTION

Dual-energy subtraction (DES) imaging can obtain chest radiographs with high contrast between nodules and healthy lung tissue, and evaluating of chest radiography and evaluating exposure conditions is crucial to obtain a high-quality diagnostic image. This study aimed to investigate the effect of the dose allocation ratio of entrance surface dose (ESD) between high- and low-energy projection in low-contrast resolution of soft-tissue images for two-shot DES imaging in digital radiography using a contrast-detail phantom (CD phantom).

METHODS

A custom-made phantom mimicking a human chest that combined a CD phantom, polymethylmethacrylate square plate, and an aluminum plate (1-3 mm) was used. The tube voltage was 120 kVp (high-energy) and 60 kVp (low-energy). The ESD was changed from 0.1 to 0.5 mGy in 0.1 mGy increments. Dose allocation ratio of ESD between 120 kVp and 60 kVp projection was set at 1:1, 1:2, 1:3, and 2:1. Inverse image quality figure (IQF_inv) was calculated from the custom-made phantom images.

RESULTS

When the total ESD and aluminum thickness were constant, no significant difference in IQF_inv was observed under most conditions of varied dose allocation ratio. Similarly, when the total ESD and the dose allocation ratio were constant, there was no significant difference in IQF_inv based on the aluminum plate thickness.

CONCLUSION

Using IQF_inv to evaluate the quality of the two-shot DES image suggested that dose allocation ratio did not have a significant effect on low-contrast resolution of soft-tissue images.

IMPLICATIONS FOR PRACTICE

The present results provide useful information for determining exposure conditions for two-shot DES imaging.

Is the image quality of conventional chest radiography obtained from a two-layer flat panel detector affected by the internal structure of the detector?

PURPOSE

Recently developed and commercialized dual-layer flat panel detectors (DL-FPDs) with two indirect scintillators are capable of acquiring dual-energy X-ray images. However, in clinical practice, they are utilized to perform conventional radiography using diagnostic X-rays with a wide energy spectrum. The two layers of the DL-FPD may affect the obtained image quality, even when only using one layer for conventional image acquisition, and these effects are yet to be substantiated. Therefore, in this study, we quantitatively evaluated the image quality of a conventional chest radiography using DL-FPD and visually verified the characteristics of the chest anthropomorphic phantom images.

METHODS

The physical characteristics of the system were evaluated using the pre-sampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), for beam quality RQA 7 and RQA 9. In addition, the subjective visibility of the anthropomorphic chest phantom and simple objects images were compared with those of a conventional single-layer flat-panel detector (SL-FPD).

RESULTS

No significant differences were found in the MTF between the SL-FPD and DL-FPD images. In addition, a higher DQE was observed at some exposure doses and in the high spatial frequency regions wherein NNPSs were lower for DL-FPD than for SL-FPD. Furthermore, no significant differences were found in the subjective visibility of the chest phantoms in each system.

CONCLUSIONS

We concluded that the image quality of the conventional radiography acquired with DL-FPD is comparable to or better than that of the SL-FPD.

Effect of beam quality and readout direction in the edge profile on the modulation transfer function of photostimulable phosphor systems via the edge method

Purpose: The objective of this study was to investigate the effects of (i) the difference in the beam qualities on the presampled modulation transfer function (MTF) using the edge method and (ii) the readout direction of the edge profile for the photostimulable phosphor (PSP) system. Approach: The International Electrotechnical Commission (IEC) defined a technique using the "radiation qualities based on a phantom made up of an aluminum added filter" (RQA). A general radiographic system with a tube voltage of 50 kV and 9.7 mm of additional aluminum filtration was used to conform the x-ray to the IEC-specified beam quality definition RQA3. Additionally, we employed two different beams with tube voltages of 60 and 70 kV using a dental x-ray unit. The MTF was measured in the readout direction from low-to-high exposure regions and vice versa with respect to the scanning and subscanning directions of the PSP system. Results: The difference in the 50%MTF value for all directions between 60 and 70 kV averaged less than 0.05 . The 50%MTF of RQA3 was on average 0.2 lower than the value for 60 kV for each direction. For all beam qualities, no difference was observed between the MTFs measured in the readout direction from the low-to-high exposure regions and vice versa. Conclusions: The MTFs, measured using the dental x-ray unit, were unaffected by the tube voltage, and they were slightly higher than those measured using the RQA3. Furthermore, the MTF was unaffected by the differences in the readout directions of the edge profile.

X-ray dose reduction using additional copper filtration for dental cone beam CT

This study aims to quantitatively evaluate the effect of additional copper-filters (Cu-filters) on the radiation dose and contrast-to-noise ratio (CNR) in a dental cone beam computed tomography (CBCT). The Cu-filter thickness and tube voltage of the CBCT unit were varied in the range of 0.00-0.20 mm and 70-90 kV, respectively. The CBCT images of a phantom with homogeneous materials of aluminum, air, and bone equivalent material (BEM) were acquired. The CNRs were calculated from the voxel values of each homogeneous material. The CTDI_vol was measured using standard polymethyl methacrylate CTDI test objects. We evaluated and analyzed the effects of tube current and various radiation qualities on the CNRs and CTDI_vol. We observed a tendency for higher CNR at increasing tube voltage and tube current in all the homogeneous materials. On the other hand, the CNR reduced at increasing Cu-filter thickness. The tube voltage of 90 kV showed a clear advantage in the tube current-CNR curves in all the homogeneous materials. The CTDI_vol increased as the tube voltage and tube current increased and decreased with the increase in the Cu-filter thickness. When the CNR was fixed at 9.23 of BEM at an exposure setting of 90 kV/5 mA without a Cu-filter, the CTDI_vol at 90 kV with Cu-filters was 8.7% lower compared with that at 90 kV without a Cu-filter. The results from this study demonstrate the potential of adding a Cu-filter for patient dose reduction while ensuring the image quality.

Effect of differences in pixel size on image characteristics of digital intraoral radiographic systems: a physical and visual evaluation

OBJECTIVES

To quantify and validate the effect of pixel size on a digital intraoral radiographic system according to International Electrotechnical Commission standards through physical and visual evaluations.

METHODS

The digital intraoral radiographic system used was the photostimulable phosphor imaging plate and scanner system. The system had three image capture modes: high-speed (HS), high-resolution (HR), and super high-resolution (SHR) with different pixels. The physical characteristics of the system were evaluated using presampled modulation transfer function (MTF) and the normalized noise power spectrum (NNPS). An aluminum (Al) step phantom with different depths of holes was used to acquire images under various exposure conditions. The average number of perceptible holes from all steps was plotted against each exposure dose. The results were compared to analyze the effects of pixel size on image quality of intraoral radiographs.

RESULTS

The MTF was slightly higher with SHR than with HR and HS. The NNPS with SHR showed about a 40% decrease in magnitude compared to HS. The total number of perceptible holes in the Al step phantom was higher with SHR than with HS and HR in all exposure conditions.

CONCLUSIONS

The MTF and NNPS obtained with different pixel size could be quantified by physical evaluation, and the differences were visually validated with Al step phantom. The SHR mode has the potential to decrease the radiation dose without compromising the image quality.

Anti-PD1 checkpoint inhibitor therapy in acral melanoma: a multicenter study of 193 Japanese patients

BACKGROUND

Acral melanoma (AM) is an epidemiologically and molecularly distinct entity that is underrepresented in clinical trials on immunotherapy in melanoma. We aimed to analyze the efficacy of anti-programmed cell death 1 (anti-PD-1) antibodies in advanced AM.

PATIENTS AND METHODS

We retrospectively evaluated unresectable stage III or stage IV AM patients treated with an anti-PD-1 antibody in any line at 21 Japanese institutions between 2014 and 2018. The clinicobiologic characteristics, objective response rate (ORR, RECIST), survival estimated using Kaplan-Meier analysis, and toxicity (Common Terminology Criteria for Adverse Events 4.0.) were analyzed to estimate the efficacy of the anti-PD-1 antibodies.

RESULTS

In total, 193 patients (nail apparatus, 70; palm and sole, 123) were included in the study. Anti-PD-1 antibody was used as first-line therapy in 143 patients (74.1%). Baseline lactate dehydrogenase (LDH) was within the normal concentration in 102 patients (52.8%). The ORR of all patients was 16.6% (complete response, 3.1%; partial response, 13.5%), and the median overall survival (OS) was 18.1 months. Normal LDH concentrations showed a significantly stronger association with better OS than abnormal concentrations (median OS 24.9 versus 10.7 months; P < 0.001). Although baseline characteristics were similar between the nail apparatus and the palm and sole groups, ORR was significantly lower in the nail apparatus group [6/70 patients (8.6%) versus 26/123 patients (21.1%); P = 0.026]. Moreover, the median OS in this group was significantly poorer (12.8 versus 22.3 months; P = 0.03).

CONCLUSIONS

Anti-PD-1 antibodies have limited efficacy in AM patients. Notably, patients with nail apparatus melanoma had poorer response and survival, making nail apparatus melanoma a strong candidate for further research on the efficacy of novel combination therapies with immune checkpoint inhibitors.

Computational analysis of interfractional anisotropic shape variations of the rectum in prostate cancer radiation therapy

PURPOSE

To analyze the uncertainties of the rectum due to anisotropic shape variations by using a statistical point distribution model (PDM).

MATERIALS AND METHODS

The PDM was applied to the rectum contours that were delineated on planning computed tomography (CT) and cone-beam CT (CBCT) at 80 fractions of 11 patients. The standard deviations (SDs) of systematic and random errors of the shape variations of the whole rectum and the region in which the rectum overlapped with the PTV (ROP regions) were derived from the PDMs at all fractions of each patient. The systematic error was derived by using the PDMs of planning and average rectum surface determined from rectum surfaces at all fractions, while the random error was derived by using a PDM-based covariance matrix at all fractions of each patient.

RESULTS

Regarding whole rectum, the population SDs were larger than 1.0 mm along all directions for random error, and along the anterior, superior, and inferior directions for systematic error. The deviation is largest along the superior and inferior directions for systematic and random errors, respectively. For ROP regions, the population SDs of systematic error were larger than 1.0 mm along the superior and inferior directions. The population SDs of random error for the ROP regions were larger than 1.0 mm except along the right and posterior directions.

CONCLUSIONS

The anisotropic shape variations of the rectum, especially in the ROP regions, should be considered when determining a planning risk volume (PRV) margins for the rectum associated with the acute toxicities.

Changes in standing body sway of pregnant women after long-term bed rest

Pregnant women tend to fall and increased body postural instability, namely body sway, may be one of the causative factors. We had a clinical impression that pregnant women after long-term bed rest tend to fall. We hypothesised that such women may show increased body sway, which we attempted to determine. Pregnant women (n = 161) were divided into three groups: (i) women with preterm labour after 2-week bed rest, (ii) those after 4-week bed rest, and (iii) those without bed rest or preterm labour. Body sway was analysed using stabilometry, that is, computed analysis of movement of the centre of gravity. The 3 groups fundamentally showed the same stabilometric measurements. Women with oedema showed greater medial-lateral sway than those without it. Factors other than oedema yielded no differences in stabilometric parameters. Long-term bed rest fundamentally did not increase body sway to the extent that stabilometry could reveal it. It may be prudent to consider that pregnant women with oedema tend to fall.

Gamma-aminobutyric acid (GABA) and cell proliferation: focus on cancer cells

In addition to its role in the adult mammalian nervous system as an inhibitory neurotransmitter, gamma-aminobutyric acid (GABA) is involved in the proliferation, differentiation, and migration of several kinds of cells including cancer cells. GABA is synthesized predominantly from glutamate by glutamate decarboxylase and exerts its effects via ionotropic GABA(A) receptors and/or metabotropic GABA(B) receptors. In this review, the current state of knowledge regarding the role of the GABAergic system in peripheral nonneuronal cell proliferation is described, and recent advances in elucidation of the mechanisms leading to cell proliferation are discussed.

Antigen-presenting cells expressing glutamate decarboxylase 67 were identified as epithelial cells in glutamate decarboxylase 67-GFP knock-in mouse thymus

Glutamate decarboxylase (GAD), which has two isoforms, GAD65, and GAD67, is responsible for synthesis of the major inhibitory neurotransmitter, gamma-aminobutyric acid. GAD is expressed predominantly in the central nervous system; recent reports suggest that GAD is also expressed in non-neuronal organs including the pancreas. In the pancreatic islets, GAD serves as one of the autoantigens in type I diabetes mellitus. Recent flow cytometric analyses have shown that a variety of self-antigens, including GAD, are ectopically transcribed and expressed in particular cell populations of the thymus, although consensus concerning the cellular phenotype has not been obtained. The aim of this study was to clarify the localization and cellular phenotype of GAD67-expressing cells in the thymus at a cellular level with a novel approach using GAD67-green fluorescent protein (GFP) knock-in mice, in which GFP is expressed specifically in GAD67-positive cells. GFP-positive cells were detected in the thymic medulla and were identified as epithelial cells by immunohistochemistry. Almost all GFP-positive cells were positive for major histocompatibility complex (MHC) class II antigen staining and were positive for both cytokeratin and Ulex Europaeus Agglutinin I, markers of medullary thymic epithelial cells, but were negative for CD11c, Gr-1, and CD45, markers of dendritic cells, macrophages, and B-lymphocytes, respectively.

Anomalous suppression of superfluidity in 4He confined in a nanoporous glass

We explore the superfluidity of 4He confined in a porous glass, which has nanopores of 2.5 nm in diameter, at pressures up to 5 MPa. With increasing pressure, the superfluidity is drastically suppressed, and the superfluid transition temperature approaches 0 K at some critical pressure, Pc approximately 3.4 MPa. The feature suggests that the extreme confinement of 4He into the nanopores induces a quantum phase transition from a superfluid to a nonsuperfluid at 0 K and at Pc.

St. John's Wort (Hypericum perforatum) induces overexpression of multidrug resistance protein 2 (MRP2) in rats: a 30-day ingestion study

St. John's Wort (Hypericum perforatum, SJW) has been used as a herbal medicine for the treatment of depression in oral doses of 900-1050 mg/day in humans. However, the ingestion of SJW was reported to cause interactions with drugs. In the present study, we examined the effects of SJW treatment on the induction of drug transporters and enzymes in rats. An immunoblot analysis was performed to quantify the expression of the transporters and enzymes. SJW was given at a dose of 400 mg/kg/day, since it was reported that 400 mg/kg/day is antidepressant effective dose in rats. When SJW was administered for 10 days, the amounts of multidrug resistance protein 2 (MRP2), glutathione S-transferase-P (GST-P) and cytochrome P450 1A2 (CYP1A2) in the liver were increased to 304%, 252% and 357% of controls, respectively, although the amounts of P-glycoprotein and multidrug resistance protein 1 were not changed. Under the same conditions, an increase of MRP2 in the kidney was not observed. The increase in the levels of each protein was maximal at 10 days after SJW treatment and lasted for at least 30 consecutive days. These results suggest that SJW induces hepatic MRP2, GST-P and CYP1A2 overexpressions, and thus, it could affect drug metabolism, conjugation and disposition.

Analysis of pathological risk factors for lymph node metastasis of submucosal invasive colon cancer

There are currently no universally accepted indications and criteria for additional surgical resection of the colorectum after endoscopic resection of the submucosal invasive cancer. The purpose of the present study is to establish accurate indications and criteria for additional surgical resection of the colorectum, based on the prediction of lymph node metastasis, after endoscopic resection of the submucosal invasive cancer. We investigated 140 submucosal invasive colorectal cancers and analyzed the pathologic factors of lymph node metastasis. The tumors were evaluated for pathologic factors in the invasive area of the submucosal carcinoma and were compared between the cases with lymph node metastasis and those without lymph node metastasis. Lymph node metastasis was observed in 13 cases (9%). Univariate logistic regression analysis showed that the depth of invasion, cribriform-type structural atypia, absence of lymphoid infiltration, lymphatic permeation, and venous permeation were statistically significant as risk factors for lymph node metastasis. Multivariate logistic regression analysis showed that the important risk factors included, in decreasing order, lymphatic permeation, absence of lymphoid infiltration, cribriform-type structural atypia, venous permeation, and depth of invasion. Submucosal invasion of 2 mm or more, and/or, depth of lymphatic permeation of 2 mm or more are risk factors for lymph node metastasis. The pathologic criteria based on our results for additional colectomy enables greater accuracy selection of patients who will undergo further surgical treatment after endoscopic resection.

Activation of the plasma kinin forming cascade along cell surfaces

Proteins of the plasma kinin-forming cascade bind to endothelial cells and activation of the cascade can be initiated along the surface. The light chain of high molecular weight kininogen (HK) (domain 5) and factor XII bind to gC1qR, the heavy chain of HK (domain 3) binds to cytokeratin 1 and the interactions are zinc dependent. Prekallikrein binds to domain 6 of HK. Antisera to gC1qR and cytokeratin 1 inhibit binding and activation. Incubation of normal plasma with endothelial cells leads to gradual conversion of prekallikrein to kallikrein, while plasma deficient in factor XII or HK are inactive within a 2-hour time frame. Thus factor XII is critical for activation to proceed. Augmentation of these reactions may occur when C1 inhibitor is functionally deficient or with ACE inhibitors which also inhibit kininases.

Factor XII-dependent contact activation on endothelial cells and binding proteins gC1qR and cytokeratin 1

Although proteins of the kinin-forming pathway are bound along the surface of endothelial cells, the mechanism of activation of this proteolytic cascade is unclear. Endothelial cell surface proteins, gC1qR and cytokeratin 1, are capable of binding Factor XII and high molecular weight kininogen (HK) in a zinc-dependent reaction thus we considered the possibility that these proteins might catalyze initiation of the cascade. Incubation of Factor XII, prekallikrein, and HK with gC1qR or cytokeratin 1 leads to a zinc-dependent and Factor XII-dependent conversion of prekallikrein to kallikrein. We also demonstrate that normal plasma is capable of activating upon interaction with the cells whereas plasma deficient in Factor XII, prekallikrein and HK do not activate. Normal plasma activation was inhibitable by antibody to gC1qR and cytokeratin 1. Thus, gC1qR and cytokeratin 1, represent potential initiating surfaces for activation of the plasma kinin-forming cascade and may do so as a result of their expression along cell surfaces.

Disordered magnetism at the metal-insulator threshold in nano-graphite-based carbon materials

The magnetism of activated carbon fibers composed of a disorder network of nanographites was investigated, where each nanographite has about 1 edge-inherited localized spin. The susceptibility, for samples situated around the metal-insulator threshold, shows a cusp around 4-7 K in addition to the presence of a field-cooling effect. These behaviors are explained in terms of disordered magnetism caused by random strengths of inter-nano-graphite antiferromagnetic interactions mediated by pi-conduction carriers.

Unfavorable effect of knee immobilization on Achilles tendon healing in rabbits

This study was undertaken to assess the effect of knee immobilization on the treatment of Achilles tendon rupture. After their Achilles tendons were severed, rabbits were divided into 2 groups. In Group A, only the ankle joint was immobilized. In Group B, both the knee and ankle joints were immobilized. At 4 weeks after surgery, both the ultimate tensile force and stiffness of the severed tendons were significantly greater in Group A than in Group B. In Group A, dense collagen fibers were seen in the repaired tendons, and the bundles of collagen fibers were parallel to one another along the axis of the tendons. In contrast, in Group B, dilated veins and capillaries were seen in the repaired tendons, and the proliferation of connective tissue containing collagen fibers was severely reduced around these veins and capillaries and was in general irregular and uneven. These results suggest that knee immobilization retards the healing of a ruptured Achilles tendon without suture, due to congestion and tension deprivation produced by keeping the tendon static.

Interaction of factor XII and high molecular weight kininogen with cytokeratin 1 and gC1qR of vascular endothelial cells and with aggregated Abeta protein of Alzheimer's disease

High molecular weight kininogen (HK) attaches to endothelial cells at separate sites on the heavy and light chains by a process which requires 15-50 microM zinc. Previously identified binding proteins include gClqR, cytokeratin 1, and the urokinase plasminogen activator receptor (U-par), however, their relative contribution to binding are not yet clarified. We have purified the binding proteins by affinity chromatography, in the presence of zinc ion, and identified cytokeratin 1 and gC1qR by amino acid sequencing of an internal peptide and by immunoblot as heavy chain and light chain binding proteins, respectively. Antibody to cytokeratin 1 inhibited HK binding to endothelial cells by 30%, antibody to gClqR inhibited HK binding to endothelial cells by 72%, and a mixture of both inhibited binding by 86%. The binding and activation of the proteins of the kinin-forming cascade along the cell surface is zinc-dependent. Similarly, proteins of the plasma kinin-forming cascade can be activated by binding to aggregated A(beta) protein of Alzheimer's disease. Activation of the cascade using purified proteins or upon addition of Abeta to plasma requires aggregation of A(beta) and the reactions are zinc-dependent. In plasma, HK is cleaved and bradykinin is liberated. The data demonstrate that aggregated A(beta) can bind and activate proenzymes of the plasma kinin-forming cascade to release bradykinin and these reactions are dependent on zinc ion.

[Acute myelocytic leukemia and plasmacytoma secondary to chemotherapy and radiotherapy in a long-term survivor of small cell lung cancer]

A 68-year-old man was given a diagnosis of lung cancer of the right upper lobe (small cell carcinoma, T 4 N 2 M 0, stage IIIB) in February 1991. The tumor diminished after chemotherapy and radiotherapy. In February 1992, a partial resection of the lower lobe of the right lung was performed because of the appearance of a metastatic tumor. In September 1994, squamous cell carcinoma developed in the lower part of the esophagus, but disappeared after radiotherapy. In February 1998, a diagnosis of myelodysplastic syndrome was made. Two months later, the patient had an attack of acute myelocytic leukemia and died of cardiac tamponade. An autopsy determined that both the lung cancer and esophageal cancer had disappeared. Acute myelocytic leukemia and plasmacytoma of lymph nodes in the irradiated area were confirmed. These were regarded as secondary malignancies induced by chemotherapy and radiotherapy.

Zinc-dependent activation of the plasma kinin-forming cascade by aggregated beta amyloid protein

Beta Amyloid proteins (Abeta) of 38, 40, and 42 amino acids long were assessed for their ability to activate the plasma kinin-forming cascade in vitro. Incubation with a mixture of Factor XII (Hageman Factor), prekallikrein, and high-molecular-weight kininogen (HK) led to conversion of prekallikrein to kallikrein that was dependent on zinc ion. No activation occurred if Factor XII was omitted. There was rapid generation of bradykinin equal to the molar HK input indicating complete cleavage. Incubation of aggregated Abeta with diluted human plasma also led to prekallikrein activation and HK cleavage. Activation of the cascade by Abeta (1-38) was dependent upon its preincubation time in buffer, suggesting that aggregation of Abeta is required, and studies with Abeta (1-40) revealed time-dependent aggregation by microscopy and augmented zinc-dependent binding of both Factor XII and HK to aggregated Abeta. These data demonstrate that aggregated Abeta can bind and activate proenzymes of the plasma kinin-forming cascade in a zinc-dependent reaction to release bradykinin and is of sufficient potency to do so at physiologic concentrations of each protein and in the presence of naturally occurring protease inhibitors.

Species variation in pharmacokinetics and opsonization of palmitoyl rhizoxin (RS-1541) incorporated in lipid emulsions

Highly lipophilic antitumor agent, palmitoyl rhizoxin (RS-1541), was incorporated into stable lipid emulsions about 100-1000nm in mean diameter consisting of triglyceride ODO and surfactant HCO-60. The pharmacokinetics of RS-1541 were studied after i.v. injection in mice, rats, rabbits, and dogs. Dog showed characteristic pharmacokinetics of RS-1541, compared with other species. RS-1541 was much more rapidly eliminated from plasma with emulsion particles in dogs than in mice, rats, and rabbits. Most amounts of injected RS-1541 were recovered in the liver six hours after administration to dogs, while less than 20% recoveries were observed for mice and rats. To clarify this species variation, opsonization of emulsion particles were evaluated. When emulsions (about 200nm in size) were opsonized by dog plasma, and intravenously injected to rats, total clearance and liver uptake of RS-1541 were increased to 1.8 fold and 2.7 fold of control values, respectively. In contrasts, emulsions opsonized by mouse, rabbit and human plasma did not show such drastic changes in pharmacokinetics of RS-1541 in rats. Furthermore, total clearance of RS-1541 for emulsions opsonized by dog plasma was increased to 1.9 fold of controls after injection to rabbits. These results indicate that opsonizing activities of dog plasma for RS-1541 emulsions are high, compared with other species. This species variation in opsonizing process probably caused the species variation in the pharmacokinetics of RS-1541 incorporated in lipid emulsions.

Morphogenesis of vertebral deformities in involutional osteoporosis. Age-related, three-dimensional trabecular structure

STUDY DESIGN

The relation between the semiquantitative data of alteration in three-dimensional trabecular structure and deformities of the vertebral body was analyzed to clarify the morphogenesis of vertebral deformities in involutional osteoporosis.

OBJECTIVES

To evaluate semiquantitatively the age-related alterations of the three-dimensional structure of trabeculae of the vertebral body and to clarify their relation to vertebral deformities in involutional osteoporosis.

SUMMARY OF BACKGROUND DATA

Recent studies have shown that bone fractures and deformities in osteoporosis do not depend only on a reduced amount of bone tissue. There is no previous study on the relation between bone deformity and the alterations of the three-dimensional structure of trabeculae.

METHODS

The second lumbar vertebrae were removed at autopsy from 25 patients who had no disease predisposing them to secondary osteoporosis and no severe vertebral deformities. The sections of the vertebral body were immersed in sodium hypochlorite solution to corrode the bone marrow. Atrophy of trabeculae and increased spacing between trabeculae were evaluated semiquantitatively under stereoscopic microscopy. The authors examined the relation between the semiquantitative data found in the autopsy vertebrae and the patterns and frequencies of each deformity of the second lumbar vertebrae in 99 patients with involutional osteoporosis.

RESULTS

The most frequent vertebral deformity was wedge-shaped vertebrae with compression of the anterosuperior portion, and the alterations of the trabecular structure of the anterosuperior portion were severe and closely related to aging. Severe trabecular alterations with no relation to aging did not necessarily cause vertebral deformity.

CONCLUSIONS

Trabecular abnormality, which is significantly correlated with aging, may be the necessary and sufficient condition for vertebral deformities in involutional osteoporosis.

Effect of neurotropin on the binding of high molecular weight kininogen and Hageman factor to human umbilical vein endothelial cells and the autoactivation of bound Hageman factor

Bradykinin is generated by activation of the plasma kallikrein-kinin (K-K) cascade and contributes to the symptoms of allergic reactions and the perception of pain. Neurotropin is a biological material obtained from inflamed rabbit skin inoculated with vaccinia virus, which is widely used clinically in Japan as an effective agent for these disorders. Factor XII (FXII) and high molecular weight kininogen (HK), two critical constituents of the plasma K-K cascade, bind to endothelial cells, and bound FXII is autoactivated in the presence of zinc ions. We have investigated the effects of Neurotropin on the interactions of FXII and HK with endothelial cells. Neurotropin inhibited the binding of both proteins to cultured human umbilical vein endothelial cells (HUVEC) and inhibited autoactivation of FXII upon HUVEC in a concentration-dependent manner. These data suggest that the ameliorating effects of Neurotropin in allergic disorders and pain syndromes may be related to this ability to inhibit activation of the K-K cascade and, consequently, the formation of bradykinin.

Laser printer optics with use of slant scanning of multiple beams

Simultaneous scanning of multiple beams in an array is an effective method to realize high-speed and high-resolution printers. The arrayed multiple beams can be generated by devices such as grating, Wollaston prism, fiber array, and laser diode array. In any of these devices, the focused spots in an array have a period several tens of times larger than the spot diameter. We propose a simultaneous scanning method suitable for these devices in which the arrayed multiple beams are arranged in a slant angle to the scanning direction to produce consecutive scan lines. Laser print experiments with two or four beams were carried out, and high-performance printing of a 431.8-mm print width, 23.6 dot/mm (i.e., 600 dot/in.) resolution, and of 541-mm/s speed were realized.

Mast cell derived heparin activates the contact system: a link to kinin generation in allergic reactions

Contact activation occurs when plasma comes in contact with negatively charged manmade surfaces but no substance that initiates contact activation in vivo has been identified. We have isolated a mast cell heparin proteoglycan (MC-HepPG) from a Furth mouse mastocytoma-derived cell line that is analogous to human tissue-type mast cell HepPG. This material and other glycosaminoglycans (GAGs) were tested for their ability to accelerate the reciprocal activation of factor XII and prekallikrein and the autoactivation of factor XII. Quantitative analysis showed the MC-HepPG to be as active as dextran sulfate on a weight basis; hog intestine heparin, dermatan sulfate, keratan polysulfate and chondroitin sulfate C were less active, other sulfated polysaccharides were essentially inactive. Incubation of MC-HepPG in 1:4 diluted plasma resulted in complete cleavage of high molecular weight kininogen in a factor XII-dependent reaction. All of the MC-HepPG dependent reactions described above were inhibited by preincubation of MC-HepPG with heparinase I and II but not by pretreatment with heparitinase, chondroitinase ABC or the serine protease inhibitor aPMSF thus indicating that heparin proteoglycan is indeed acting as an initiating 'surface'. We analysed the proteoglycan preparation by HPLC gel filtration. Fractions spanning a molecular weight range of > 400000-8000 were active initiators. Comparison of the chromatograms obtained before and after cleavage of GAG side chains from the protein core suggested that dissociated GAGs in the MW range 69000-17000 are the most active species rather than the complete proteoglycan. MC-HepPG GAGs therefore represent a physiologic macromolecule with activity comparable to non-physiological surfaces in a purified system and with the capability to induce activation of the contact system in diluted plasma. Its ability to promote kinin generation links cellular and humoral inflammatory responses in the perivasculature and provides a possible explanation for the elevated kinin levels observed after allergen exposure.

Optics for modulating multiple beams using an asymmetric multilevel phase grating and a multichannel acousto-optic modulator

Asymmetric multilevel phase gratings for generating even numbered beams have been designed, assuming that their phase patterns are formed by overlapping plural binary-phase patterns, each of which has an arbitrary phase height. The grating for four beams, which produces uniform and high intense diffraction orders of the minus first to the plus second order, is fabricated. The efficiency is 75.5%, although the theoretical efficiency is 79.9%. It is also demonstrated that the optics in which the beams from the grating are fed into a multichannel acousto-optic modulator through a Fourier-transform lens makes their successful modulation possible for pulse signals of 20-ns pulse duration.

Pathogenesis of focal and random hepatocellular necrosis in endotoxemia: microscopic observation in vivo

The present study was undertaken in rats to clarify the role of sinusoidal circulatory disturbances due to fibrin thrombi in the development of focal and random hepatocellular necrosis in endotoxemia. Sinusoidal circulation was examined microscopically in vivo in rats injected with endotoxin or heparin, or both. The sinusoids in places were occluded by adherent fibrin and neutrophils soon after endotoxin injection, and subsequently the sinusoidal blood flow stagnated, reversed, or detoured. Most of these sinusoidal circulatory disturbances recovered in a few hours. However, when the sinusoidal occlusion developed simultaneously in clusters of adjacent sinusoids, the sinusoidal circulatory disturbance persisted and induced ischemic foci and then hepatocellular coagulative necrosis. Pretreatment with heparin definitely prevented the adherence of fibrin and neutrophils to the sinusoidal walls, and focal hepatocellular necrosis did not appear. These results suggest that focal and random hepatocellular necrosis in endotoxemia is caused by circulatory disturbances due to fibrin thrombi in clusters of adjacent sinusoids.

Lipid emulsions of palmitoylrhizoxin: effects of particle size on blood dispositions of emulsion lipid and incorporated compound in rats

Emulsion formulations of various particle sizes for the highly lipophilic antitumour agent, RS-1541 (13-O-palmitoylrhizoxin), were prepared using dioctanoyldecanoylglycerol (ODO) as lipids and polyoxyethylene-(60)-hydrogenated castor oil (HCO-60) as a surfactant. These emulsions were evaluated as injectable drug carriers and compared with a colloidal solution. Both in vitro and in vivo after i.v. administration, RS-1541 was distributed into lipoproteins from the colloidal solution. When applied as emulsions of various particle sizes (124-419 nm) in vitro, RS-1541 was retained and stabilized within the emulsions. In the in vivo study, however, retention of RS-1541 in the emulsions after i.v. injection depended on their size. The small-particle emulsions (94-112 nm) resulted in long retention, and the large-particle emulsions (415-474 nm) led to short retention. Lipolysis rates of emulsion particles by lipoprotein lipase also depended on their size, indicating rapid lipolysis for small-particle emulsions (133 nm). However, the lipolysis was not such an extensive one, showing 10-30% release of capric acid from ODO within 6 h. Blood dispositions of capric acids approximately paralleled those of RS-1541 after i.v. injection of various particle size emulsions (130-368 nm) to rats, although relatively rapid eliminations of capric acids compared with RS-1541 were observed for the small-particle size emulsions (130 nm). These results suggest that when injected as emulsion formulations, the highly lipophilic antitumour agent, RS-1541, has behaviour similar to that of the emulsion particles in the body, which is dependent on the size of the latter. Thus, by properly selecting the particle size, lipid emulsions consisting of ODO and HCO-60 are expected to be effective and useful DDS carriers for RS-1541.

Lipid emulsions of palmitoylrhizoxin: effects of composition on lipolysis and biodistribution

Four types of lipid emulsion for highly lipophilic antitumour agent RS-1541 (13-O-palmitoylrhizoxin) with mean particle diameters of 200-260 nm were prepared using soybean oil (SOY) or dioctanoyldecanoylglycerol (ODO) for the oil phase and lecithin (LEC) or polyoxyethylene-(60)-hydrogenated castor oil (HCO-60) for surfactants. The lipolysis rate of HCO-60-emulsified emulsions by lipoprotein lipase was much slower than that of LEC-emulsified emulsions. Particle sizes of emulsions incubated in plasma with the lipase for six hours were 75%, 79%, 101%, and 93% of initial values for SOY/LEC, ODO/LEC, SOY/HCO-60, and ODO/HCO-60 emulsions, respectively, showing an apparent size decrease for LEC-emulsified emulsions. In rats, uptake clearance values of SOY/LEC and ODO/LEC emulsions of RS-1541 in the reticuloendothelial system (RES) were 81.2 and 135.3 mL h(-1), respectively, and AUC values were 4.0 and 1.3 microg h mL(-1), respectively. In contrast, RES uptake clearances of HCO-60 emulsions of RS-1541 were considerably lower (4.2 mL h(-1) for SOY/HCO-60; 2.2 mL h(-1) for ODO/HCO-60), resulting in high AUC values (35.4 microg h mL(-1) for SOY/ HCO-60; 63.9 microg h mL(-1) for ODO/HCO-60). The concentrations of RS-1541 in tumour tissues after an intravenous administration of ODO/HCO-60 emulsions of RS-1541 to mice bearing solid tumour M5076 sarcoma were about ten times higher than those after the administration of SOY/LEC emulsions. These results indicate that HCO-60 emulsions, compared with conventional LEC emulsions, are more stable to lipoprotein lipase and show low uptakes by RES organs, long circulations in the plasma, and high distributions in tumours. Thus, these sterically stabilized emulsions could show potential as effective carriers for highly lipophilic antitumour agents to enhance the drug delivery in tumours.

Highly selective aldose reductase inhibitors. 1. 3-(Arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids

A series of 3-(arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids (1) was prepared and tested for aldose reductase (AR) and aldehyde reductase (ALR) inhibitory activities. These compounds showed strong inhibitory activity against AR without significant inhibitory activity for ALR. The ratio of IC50(ALR)/IC50(AR) was > 1000 in some compounds. On the basis of pharmacological tests such as the recovery of reduced motor nerve conduction velocity and toxicological profile, 3-(3-nitrobenzyl)-2,4,5-trioxoimidazolidine-1-acetic acid (NZ-314) was selected as the candidate for clinical development.

Interruption of pulmonary arterial flow with inadequate ventilation leads to pulmonary infection

We examined the effect of interruption of pulmonary arterial flow and inadequate ventilation on the development of pulmonary infarction in rats. Pulmonary arterial flow was blocked by the injection of agar into the inferior vena cava and inadequate ventilation was produced by obstructing the left main bronchus with a polypropylene tip. Histological and angiographic examination of the lung demonstrated that: pulmonary artery embolism alone does not induce pulmonary infarction; obstruction of a bronchus does not induce significant changes, but that pulmonary infarction develops when pulmonary artery embolism and obstruction of a bronchus occur simultaneously. It has been thought that pulmonary infarction is caused by acute obstruction of a pulmonary artery, however, the alveolar walls are supplied with oxygen by both the pulmonary circulation and by ventilation. Interruption of pulmonary arterial flow alone is probably not sufficient to induce pulmonary infarction, which is probably caused by deficiency of oxygen supply to the alveolar walls by a synergy between interruption of pulmonary arterial flow and inadequate ventilation.

Pattern of nasal secretions during experimental influenza virus infection

To define the pattern of secretion production during influenza virus infection, 28 adult subjects were inoculated with influenza-A virus (H1N1) and cloistered for a period of 8 days. On each day, symptoms associated with virus infection were scored, nasal secretions were collected and nasal lavages were performed. Recovered lavage fluids were submitted for virus culture and assayed for proteins, histamine, and bradykinin. Twenty-one subjects were infected with influenza-A virus and had significant increases in daily secretion weights and symptom scores extending from day 2 to 7, post-inoculation. Plasma-derived proteins in the nasal lavage fluids showed an early increase to peak at day 4 and then decreased. Glandular proteins showed a later increase to peak at day 5. Bradykinin but not histamine was significantly elevated and tracked the changes in the glandular proteins. In contrast, a shallow increase in symptoms confined to day 2 post-inoculation, but no increase in daily secretion weights was documented in the seven uninfected subjects. There, an increase in plasma proteins was observed on days 1 and 2, but no change in glandular proteins was obvious. These results support a biphasic secretory response during influenza-virus infection with transudation dominating the early period and glandular secretions contributing later.