Critical-sized marginal defects around implants in the rabbit mandible

BACKGROUND

The mandible of the rabbit is considered a reliable model to be used to study bone regeneration in defects. The aim of the present study was to evaluate the formation of new bone around implants installed in defects of either 5 or 10 mm in the mandible of rabbits.

MATERIALS AND METHODS

In 12 rabbits, 3 mm deep circumferential defect, either 5 or 10 mm in diameter, were prepared bilaterally and an implant was placed in the center. A collagen membrane was placed to close the entrance. After 10 weeks, biopsies were taken, histological slides were prepared, and different regions of the defects were analyzed.

RESULTS

Similar amounts of new bone were found in both defects. However, most of the 5 mm defects were filled with new bone. New bone was observed closing the entrance of the defect and laid onto the implant surface. Only in a few cases the healing was incomplete. Despite a similar percentage of new bone found within the 10 mm defects, the healing was incomplete in most of the cases, presenting a low rate of bone formation onto the implant surface within the defect. Only one case presented the closure of the entrance.

CONCLUSIONS

The dimensions of the defect strongly influenced the healing so that a circumferential marginal defect of 10 mm around an implant in the mandible body should be considered a critical-sized defect. The presence of the implant and of residues of teeth might have strongly influenced the healing.

Biocompatibility of dental implants coated with hydroxyapatite using pulsed Er:YAG laser deposition

We aimed to improve the biocompatibility and osteoinductive potential of Ti implants using a simulated intraoral hydroxyapatite (HAp) coating. We devised a novel surface treatment for aggressive induction of osteoblast adhesion and bone regeneration on the implant surface. A thin α-tricalcium phosphate (α-TCP) film was deposited on the implant surface using a pulsed Er:YAG laser. The coating was converted to HAp through artificial saliva immersion, which was confirmed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM showed needle-like HAp crystals on the Ti disks and sandblasted implant surfaces after immersion in artificial saliva for 96 h. Microcomputed tomography and histological evaluation 4 and 8 weeks after implantation into beagle dog mandibles showed that the HAp-coated implant was biocompatible and exhibited superior osteoinduction compared to that of sandblasted implants. Coating the implant surface with HAp using an Er:YAG laser has potential as a new method of the implant-surface debridement.

Critical-sized marginal defects around implants treated with xenografts in rabbits

BACKGROUND

Healing of critical-size defects is a well-known problem that has been challenged in several studies. The aim of the experiment was to evaluate bone formation and osseointegration of implants installed in critical defects of the mandibular body simultaneously grafted with Bio-Oss® or Cerabone®.

MATERIAL AND METHODS

Defects, 10 mm wide and 3 mm deep, were prepared at both lateral aspects of the mandible in 12 rabbits. One implant was installed in the center of the defect, and bovine xenografts produced either at low (Bio-Oss®; Low-T) or high (Cerabone®; High-T) temperatures were used to fill the defects. A collagen membrane was placed to cover the sites. Healing was evaluated 10 weeks after surgery.

RESULTS

In both groups, most sites showed optimal healing with closure of the coronal entrance of the defects. However, residual defects occupied by soft tissues and biomaterial particles were observed, even though generally limited to some regions of the defect. Osseointegration of the implant surface in the region of the defect was poor in both groups.

CONCLUSIONS

Circumferential marginal critical-size defects around implants filled with bovine xenografts presented regions with a complete healing in both groups. However, the healing was not complete at all regions in most defects; therefore, a complete optimal healing of critical-size marginal defects cannot be predicted.

Histological Comparison of Collagenated Cancellous Equine Bone Blocks Used as Inlay or Onlay for Lateral Bone Augmentation in Rabbits

BACKGROUND

The conformation of the recipient site for an inlay graft presents an increased contact with the parent bone compared to an onlay graft. This might favor bone growth within the inlay compared to onlay grafts. Hence, the objective of this study was to compare the bone incorporation and remodeling processes of xenogeneic en bloc grafts placed using two bone grafting techniques, i.e., onlay vs. inlay.

METHODS

In this prospective, randomized, split-mouth study (test and control sides in the same animal), two bone grafting techniques were comparatively evaluated. The lateral aspect of the rabbit mandible was used as the recipient site, bilaterally. On one side of the mandible, the cortical bone was perforated with drills to allow a better bone formation from the bone wound and the marrow spaces. A xenogeneic bone block was fixed in the center of the prepared region, representing the onlay site. On the other side of the mandible, a 7 mm wide and 3 mm deep circumferential defect was prepared using trephines and drills. A xenogeneic bone block was fixed in the center of the defect, representing the inlay site. Two healing periods were applied in the study: 2 and 10 weeks, each represented by 10 rabbits (n = 10 for each period).

RESULTS

After 2 weeks of healing, the mean percentage of new bone was 10.4% and 23.3% at the onlay and inlay grafts, respectively (p = 0.022). After 10 weeks of healing, new bone increased to 13.2% at the onlay sites and 25.4% at the inlay sites (p = 0.080). In the 10-week period, the inlay grafts presented a homogeneous growth of new bone in all regions, while in the onlay grafts, low percentages of new bone were observed in the external regions.

CONCLUSION

The percentage of new bone increased faster and was higher in the inlay grafts than in the onlay grafts. This outcome might be related to the self-contained conformation of the recipient site in the inlay group, which offered more sources for new bone formation compared to the one-wall conformation of the recipient sites in the onlay group. The osteoconductive properties of the biomaterial allowed the newly formed bone to reach the most peripheral regions in both groups. The osteoconductive properties of the biomaterial, together with the protection offered by the collagen membrane, allowed marginal closure of the defects by newly formed bone in the inlay group.

Augmentation of IFN-γ by bone marrow derived immune cells in the presence of severe suppression of IFN-γ in gingivae induced by zoledronic acid and denosumab in Hu-BLT mice model of ONJ

Introduction

The potential mechanisms governing drug induced osteonecrosis of the jaw (ONJ) is not well understood, and is one of the objectives of this study. Thus, we tested the release of IFN-γ within different immune compartments including bone marrow and gingivae upon treatment with zoledronic acid (ZOL) and denosumab which are known to induce ONJ in susceptible individuals.

Methods

We used humanized-BLT mouse model for the in-vivo studies reported in this paper. To determine the effects of zoledronic acid and denosumab on IFN-γ secretion and NK cell-mediated cytotoxicity; peripheral blood, bone marrow, spleen and gingiva were obtained after the injection of ZOL and denosumab in mice.

Results

Percentages of B cells are much higher in wild-type mice whereas the proportions of immune subsets in humans and reconstituted hu-BLT peripheral-blood are similar. Therefore, hu-BLT mice are preferable model to study human disease, in particular, immune-pathologies induced by ZOL and denosumab. Both agents resulted in a severe suppression of IFN-γ in the gingiva, whereas they heightened the release of IFN-γ and NK cell-mediated cytotoxicity by the BM-derived immune cells. ZOL increased the IFN-γ secretion by the spleen and peripheral blood immune cells, whereas denosumab decreased the release IFN-γ by these cells significantly.

Discussion

ZOL and denosumab may likely suppress IFN-γ secretion in gingiva through different mechanisms. In addition, to the suppression of IFN-γ secretion, denosumab mediated effect could in part be due to the decrease in the bone resorptive function of osteoclasts due to the induction of antibody dependent cellular cytotoxicity and lysis of osteoclasts, whereas ZOL is able to mediate cell death of osteoclasts directly. Suppression of IFN-gamma in gingiva is largely responsible for the inhibition of immune cell function, leading to dysregulated osteoblastic and osteoclastic activities. Restoration of IFN-gamma in the local microenvironment may result in establishment of homeostatic balance in the gingiva and prevention of osteonecrosis of jaw.

Design and Synthesis of Cathepsin-K-Activated Osteoadsorptive Fluorogenic Sentinel (OFS) Probes for Detecting Early Osteoclastic Bone Resorption in a Multiple Myeloma Mouse Model

We describe the design and synthesis of OFS-1, an Osteoadsorptive Fluorogenic Sentinel imaging probe that is adsorbed by hydroxyapatite (HAp) and bone mineral surfaces, where it generates an external fluorescent signal in response to osteoclast-secreted cathepsin K (Ctsk). The probe consists of a bone-anchoring bisphosphonate moiety connected to a Förster resonance energy transfer (FRET) internally quenched fluorescent (IQF) dye pair, linked by a Ctsk peptide substrate, GHPGGPQG. Key structural features contributing to the effectiveness of OFS-1 were defined by structure-activity relationship (SAR) and modeling studies comparing OFS-1 with two cognates, OFS-2 and OFS-3. In solution or when preadsorbed on HAp, OFS-1 exhibited strong fluorescence when exposed to Ctsk (2.5-20 nM). Time-lapse photomicrographs obtained after seeding human osteoclasts onto HAp-coated well plates containing preadsorbed OFS-1 revealed bright fluorescence at the periphery of resorbing cells. OFS-1 administered systemically detected early osteolysis colocalized with orthotopic engraftment of RPMI-8226-Luc human multiple myeloma cells at a metastatic skeletal site in a humanized mouse model. OFS-1 is thus a promising new imaging tool for detecting abnormal bone resorption.

Rescue bisphosphonate treatment of alveolar bone improves extraction socket healing and reduces osteonecrosis in zoledronate-treated mice

Bisphosphonate (BP)-related osteonecrosis of the jaw, previously known as BRONJ, now referred to more broadly as medication-related osteonecrosis of the jaw (MRONJ), is a morbid condition that represents a significant risk for oncology patients who have received high dose intravenous (IV) infusion of a potent nitrogen containing BP (N-BP) drug. At present, no clinical procedure is available to prevent or effectively treat MRONJ. Although the pathophysiological basis is not yet fully understood, legacy adsorbed N-BP in jawbone has been proposed to be associated with BRONJ by one or more mechanisms. We hypothesized that removal of the pre-adsorbed N-BP drug common to these pathological mechanisms from alveolar bone could be an effective preventative/therapeutic strategy. This study demonstrates that fluorescently labeled BP pre-adsorbed on the surface of murine maxillo-cranial bone in vivo can be displaced by subsequent application of other BPs. We previously described rodent BRONJ models involving the combination of N-BP treatment such as zoledronate (ZOL) and dental initiating factors such as tooth extraction. We further refined our mouse model by using gel food during the first 7 days of the tooth extraction wound healing period, which decreased confounding food pellet impaction problems in the open boney socket. This refined mouse model does not manifest BRONJ-like severe jawbone exposure, but development of osteonecrosis around the extraction socket and chronic gingival inflammation are clearly exhibited. In this study, we examined the effect of benign BP displacement of legacy N-BP on tooth extraction wound healing in the in vivo model. Systemic IV administration of a low potency BP (lpBP: defined as inactive at 100 μM in a standard protein anti-prenylation assay) did not significantly attenuate jawbone osteonecrosis. We then developed an intra-oral formulation of lpBP, which when injected into the gingiva adjacent to the tooth prior to extraction, dramatically reduced the osteocyte necrosis area. Furthermore, the tooth extraction wound healing pattern was normalized, as evidenced by timely closure of oral soft tissue without epithelial hyperplasia, significantly reduced gingival inflammation and increased new bone filling in the extraction socket. Our results are consistent with the hypothesis that local application of a rescue BP prior to dental surgery can decrease the amount of a legacy N-BP drug in proximate jawbone surfaces below the threshold that promotes osteocyte necrosis. This observation should provide a conceptual basis for a novel strategy to improve socket healing in patients treated with BPs while preserving therapeutic benefit from anti-resorptive N-BP drug in vertebral and appendicular bones.

Neuronal PAS Domain 2 (Npas2)-Deficient Fibroblasts Accelerate Skin Wound Healing and Dermal Collagen Reconstruction

The circadian clock, which consists of endogenous self-sustained and cell-autonomous oscillations in mammalian cells, is known to regulate a wide range of peripheral tissues. The unique upregulation of a clock gene, neuronal PAS domain protein 2 (Npas2), observed along with fibroblast aging prompted us to investigate the role of Npas2 in the homeostasis of dermal structure using in vivo and in vitro wound healing models. Time-course healing of a full-thickness skin punched wound exhibited significantly faster wound closure in Npas2-/- mice than wild-type (WT) C57Bl/6J mice. Dorsal skin fibroblasts isolated from WT, Npas2+/-, and Npas2-/- mice exhibited consistent profiles of core clock gene expression except for Npas2 and Per2. In vitro behavioral characterizations of dermal fibroblasts revealed that Npas2-/- mutation was associated with increased proliferation, migration, and cell contraction measured by floating collagen gel contraction and single-cell force contraction assays. Npas2 knockout fibroblasts carrying sustained the high expression level of type XII and XIV FAICT collagens and synthesized dermis-like thick collagen fibers in vitro. Confocal laser scanning microscopy demonstrated the reconstruction of dermis-like collagen architecture in the wound healing area of Npas2-/- mice. This study indicates that the induced Npas2 expression in fibroblasts may interfere with skin homeostasis, wound healing, and dermal tissue reconstruction, providing a basis for novel therapeutic target and strategy. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.

Neuronal PAS domain 2 (Npas2) facilitated osseointegration of titanium implant with rough surface through a neuroskeletal mechanism

Titanium (Ti) biomaterials have been applied to a wide range of implantable medical devices. When placed in bone marrow, Ti-biomaterials integrate to the surrounding bone tissue by mechanisms that are not fully understood. We have previously identified an unexpected upregulation of circadian clock molecule neuronal PAS domain 2 (Npas2) in successfully integrated implant with a rough surface. This study aimed to elucidate the molecular mechanism of osseointegration through determining the role of Npas2. Human bone marrow stromal cells (BMSC) that were cultured on a Ti disc with SLA surface exhibited increased NPAS2 expression compared to BMSC cultured on a machined surface. A mouse model was developed in which miniature Ti implants were surgically placed into femur bone marrow. The implant push-out test and bone-to-implant contact measurements demonstrated the establishment of osseointegration in 3 weeks. By contrast, in Npas2 functional knockout (KO) mice, the implant push-out value measured for SLA surface Ti implant was significantly decreased. Npas2 KO mice demonstrated normal femur bone structure surrounding the Ti implant; however, the recovered implants revealed abnormal remnant mineralized tissue, which lacked dense collagen architecture typically found on recovered implants from wild type mice. To explore the mechanisms leading to the induced Npas2 expression, an unbiased chemical genetics analysis was conducted using mouse BMSC carrying an Npas2-reporter gene for high throughput screening of Library of Pharmacologically Active Compounds. Npas2 modulating compounds were found clustered in regulatory networks of the α2-adrenergic receptor and its downstream cAMP/CREB signaling pathway. Mouse primary BMSC exposed to SLA Ti disc significantly increased the expression of α2-adrenergic receptors, but the expression of β2-adrenergic receptor was unaffected. Our data provides the first evidence that peripheral clock gene component Npas2 plays a role in facilitating the enhanced osseointegration through neuroskeletal regulatory pathways induced by BMSC in contact with rough surface Ti implant.

Titanium biomaterials with complex surfaces induced aberrant peripheral circadian rhythms in bone marrow mesenchymal stromal cells

Circadian rhythms maintain a high level of homeostasis through internal feed-forward and -backward regulation by core molecules. In this study, we report the highly unusual peripheral circadian rhythm of bone marrow mesenchymal stromal cells (BMSCs) induced by titanium-based biomaterials with complex surface modifications (Ti biomaterial) commonly used for dental and orthopedic implants. When cultured on Ti biomaterials, human BMSCs suppressed circadian PER1 expression patterns, while NPAS2 was uniquely upregulated. The Ti biomaterials, which reduced Per1 expression and upregulated Npas2, were further examined with BMSCs harvested from Per1::luc transgenic rats. Next, we addressed the regulatory relationship between Per1 and Npas2 using BMSCs from Npas2 knockout mice. The Npas2 knockout mutation did not rescue the Ti biomaterial-induced Per1 suppression and did not affect Per2, Per3, Bmal1 and Clock expression, suggesting that the Ti biomaterial-induced Npas2 overexpression was likely an independent phenomenon. Previously, vitamin D deficiency was reported to interfere with Ti biomaterial osseointegration. The present study demonstrated that vitamin D supplementation significantly increased Per1::luc expression in BMSCs, though the presence of Ti biomaterials only moderately affected the suppressed Per1::luc expression. Available in vivo microarray data from femurs exposed to Ti biomaterials in vitamin D-deficient rats were evaluated by weighted gene co-expression network analysis. A large co-expression network containing Npas2, Bmal1, and Vdr was observed to form with the Ti biomaterials, which was disintegrated by vitamin D deficiency. Thus, the aberrant BMSC peripheral circadian rhythm may be essential for the integration of Ti biomaterials into bone.

Plasticity of Myeloid Cells during Oral Barrier Wound Healing and the Development of Bisphosphonate-related Osteonecrosis of the Jaw

Injury to the barrier tissue initiates a rapid distribution of myeloid immune cells from bone marrow, which guide sound wound healing. Bisphosphonates, a widely used anti-bone resorptive drug with minimal systemic side effects, have been linked to an abnormal wound healing in the oral barrier tissue leading to, in some cases, osteonecrosis of the jaw (ONJ). Here we report that the development of ONJ may involve abnormal phenotypic plasticity of Ly6G+/Gr1+ myeloid cells in the oral barrier tissue undergoing tooth extraction wound healing. A bolus intravenous zoledronate (ZOL) injection to female C57Bl/6 mice followed by maxillary first molar extraction resulted in the development of ONJ-like lesion during the second week of wound healing. The multiplex assay of dissociated oral barrier cells exhibited the secretion of cytokines and chemokines, which was significantly modulated in ZOL mice. Tooth extraction-induced distribution of Ly6G+/Gr1+ cells in the oral barrier tissue increased in ZOL mice at week 2. ONJ-like lesion in ZOL mice contained Ly6G+/Gr1+ cells with abnormal size and morphology as well as different flow cytometric staining intensity. When anti-Ly6G (Gr1) antibody was intraperitoneally injected for 5 days during the second week of tooth extraction, CD11b+GR1(hi) cells in bone marrow and Ly6G+ cells in the oral barrier tissue were depleted, and the development of ONJ-like lesion was significantly attenuated. This study suggests that local modulation of myeloid cell plasticity in the oral barrier tissue may provide the basis for pathogenesis and thus therapeutic as well as preventive strategy of ONJ.

Chelation of trace elements in preservation medium influences the quality of boar spermatozoa during liquid preservation at 5°C for 4 weeks

BACKGROUND

The addition of a metal chelator, ethylenediaminetetraacetic acid (EDTA), to semen extender has the purpose of capturing trace element ions.

OBJECTIVE

This study was conducted to evaluate the effects of EDTA on the quality and in vitro fertilisability of liquid-preserved boar spermatozoa.

METHODS

In Experiment 1, semen samples were preserved in the semen extender supplemented with 0, 3, 6, or 12 mM of Na-EDTA at 5 degree C for 4 weeks. In Experiment 2, semen samples were preserved in the extender supplemented with 3 mM of Na-EDTA, Ca-EDTA, or Zn-EDTA and without chelator EDTA.

RESULTS

When Na-EDTA was used as a chelating substance in the extender, 3 mM was a most suitable concentration for sperm motility and viability after cold preservation. The supplementation of 3 mM Ca-EDTA had advantages regarding sperm motility, viability and plasma membrane integrity.

CONCLUSION

Our findings indicate that 3 mM Ca-EDTA is the most suitable metal-chelating substance for the liquid preservation of boar semen.

Hypoxic condition promotes differentiation and mineralization of dental pulp cells in vivo

AIM

To investigate the behaviour of dental pulp cells under hypoxic conditions in vivo using an experimental animal model.

METHODOLOGY

A mini-screw was inserted into the inferior dental nerve canal of rats to arrest the blood supply, which resulted in a reduced oxygen level in the dental pulps of molar teeth used for the experimental group. The decrease in blood supply was evaluated by injected India ink in transparent specimens. The hypoxia marker hypoxyprobe-1 was investigated by immunohistochemical staining. The mRNA expressions of ATP-binding cassette transporter (ABC) G2 (ABCG2) which is a marker for the capacity to excrete metabolites and for stem-like cells as well as dentine sialophosphoprotein (DSPP) and osteocalcin (OCN) which are markers for mineralization were evaluated by RT-PCR. Protein was evaluated by immunohistochemical staining using ABCG2, dentine sialoprotein (DSP) and OCN.

RESULTS

The evaluation of India ink indicated a decreased blood supply in the transparent specimens, and hypoxyprobe-1 immunohistochemical staining showed positive expression. ABCG2, DSPP and OCN mRNA expressions increased at 7 and 14 days. Immunohistochemically, ABCG2, DSP and OCN-positive cells were localized in the odontoblastic layer.

CONCLUSIONS

Hypoxic conditions promoted mineralization and differentiation of dental pulp cells of the odontoblastic layer.

Students' opinion of a predoctoral implant training program

Implant treatment today is highly predictable and provides valid restorative options for the completely or partially edentulous patient. In Japan, many dental care facilities have incorporated implant treatment, and such treatment is no longer rare. For predoctoral students, the educational environment related to implants is not always applicable in present clinical settings. In this article, we describe the implant training program developed at our university for predoctoral education, and we report the changes in student opinions regarding implant treatment by comparing pre- and post-training opinions. The newly developed models for implant training were effective in increasing student understanding that implant treatment is one prosthetic option for restoring missing teeth. In a survey of predoctoral students, responses indicating negative opinions toward implant treatment decreased after training, and responses indicating positive opinions increased. These findings indicated that this training was effective in deepening student understanding of implant treatment.

Anastomosis between the hepatic artery and the extrahepatic collateral or between extrahepatic collaterals: observation on angiography

Transcatheter arterial chemoembolisation for hepatocellular carcinoma is widely carried out not only through the hepatic artery but also through the extrahepatic collateral pathways. Anatomically, there are many anastomoses between the hepatic artery and the extrahepatic collateral as well as among the extrahepatic collaterals. However, these anastomoses may not be shown on angiography because the anastomosing branches are too small. These anastomoses may not only interfere with effective control of hepatocellular carcinoma by transcatheter arterial chemoembolisation but also cause unexpected procedure-related complications. Therefore, radiologists should have sufficient knowledge of these underlying anastomoses. In this report, we present our angiographic images.

Surface dose measurement in patients and physicians and effective dose estimation in patients during uterine artery embolisation

Surface dose monitoring in patients and physicians during 29 uterine artery embolisation (UAE) procedures was performed using photoluminescence dosemeters and thermo-luminescence dosemeters. Organ or tissue doses were measured with an anthropomorphic phantom using UAE exposure conditions averaged from the 29 cases, and effective doses were estimated for the patient. Entrance surface dose of the patients at the maximum dose position ranged from 121.5 to 1650 mGy. Estimated doses ranged from 3.16 to 43 mGy for the ovary and from 3.8 to 51.8 mGy for the uterus. The effective dose was 1.09-14.8 mSv. Monitored doses on the body surface of physicians were relatively high in the upper arm (5.41+/-1.52 to 163+/-17.25 microGy) and the hand and fingers (0.85+/-1.18 to 222+/-16.4 microGy).

A comparison of the production of reactive oxygen species by suspended particulate matter and diesel exhaust particles with macrophages

Oxidative stress has emerged as a pivotal mechanism that underlies the toxic pulmonary effects of suspended particulate matter (SPM). Experimental evidence shows that redox-active transition metals, redox-cycling quinoids, and polycyclic aromatic hydrocarbons (PAHs) contained in SPM act synergistically, producing reactive oxygen species (ROS). The direct production of superoxide anion and the damaging hydroxyl radical has been studied in aqueous and dimethyl sulfoxide (DMSO) suspensions of SPM both with and without H2O2; however, no study has reported on the release of ROS from ingesting macrophages with SPM. We investigated the time course of the ability to induce lucigenin-dependent chemiluminescence (CL) from human monocyte-derived macrophages exposed to SPM, carbon black particles, and diesel exhaust particles (DEP). We also examined hydroxyl radical generation from the same experimental system using the 2-deoxy-d-robse method. We found an increase of CL for SPM, but not for carbon black particles or for DEP. Hydroxyl radical generation was observed in both SPM and DEP, but the release from DEP was more frequent than that from SPM. These results suggest that certain components of SPM are important in the response of ROS from ingesting macrophages with SPM, and that those components are discharged from SPM into the atmosphere.

[Survey of surgical treatment of malignant pleural mesothelioma in Japan]

Surgical results of patients with malignant pleural mesothelioma (MPM) in Japan was surveyed from the results of a questionnaire sent to members of the Japan Lung Cancer Society. and a total of 132 surgical cases of MPM from 1997 to 2002 were analyzed. They consisted of 112 males and 20 females. By histological type, 87 cases had epithelial type, 10 had sarcomatous type, 26 had mixed type and 2 had uncommon type of MPM (the histology of 7 cases was not indicated). As to the surgical mode, extrapleural pneumonectomy (EPP) was performed in 73 cases, and limited surgery such as decortication and tumorectomy was performed in 59 cases. The tumor was potentially completely resected in 83 cases. Postoperative adjuvant therapy was performed in 56 cases. The 1-, 2- and 3-year survival rates of the present cases were 54, 33 and 21%, respectively, and the perioperative mortality rate was 5%. These survival and mortality rates in the present series were almost similar to those of the MPM cases in the previously reported series from 1987 to 1996 by Takagi et al. According to Cox regression analysis, prognostic factors for survival included postoperative adjuvant therapy (p=0.003) and complete resection (p=0.037) significantly, and International Mesothelioma Interest Group (IMIG) stage (p=0.051) and performance status (p=0.086) with a marginal significance, indicating that complete surgical resection of the tumor and perioperative adjuvant therapy could be effective treatment for MPM in Japan. Thus, the development of multimodality therapy including surgical treatment for this disease may be required to improve surgical results of MPM patients.

Effect of size of man-made and natural mineral fibers on chemiluminescent response in human monocyte-derived macrophages

Fiber size is an important factor in the tumorigenicity of various mineral fibers and asbestos fibers in animal experiments. We examined the time course of the ability to induce lucigenin-dependent chemiluminescence (CL) from human monocyte-derived macrophages exposed to Japan Fibrous Material standard reference samples (glass wool, rock wool, micro glass fiber, two types of refractory ceramic fiber, refractory mullite fiber, potassium titanium whisker, silicon carbide whisker, titanium oxide whisker, and wollastonite). We determined how fiber length or width might modify the response of cells. We found that the patterns of time-dependent increase of CL (sigmoid type) were similar for each sample except wollastonite. We observed a strong correlation between geometric-mean length and ability to induce CL in seven samples > 6 microm in length over the time course (largest r(2) = 0.9760). Although we also observed a close positive correlation between geometric-mean width and the ability to induce CL in eight samples < 1.8 microm in width at 15 min (r(2) = 0.8760), a sample of 2.4 microm in width had a low ability to induce CL. Moreover, the relationship between width and the rate of increase in ability to induce CL had a negative correlation at 30-60 min (largest r(2) = 0.7473). Our findings suggest that the release of superoxide from macrophages occurs nonspecifically for various types of mineral fibers depending on fiber length.

Epidemiology of occupational asbestos-related diseases in China

In 1950s and 60s, asbestosis had been a major health hazard for asbestos exposed workers. In the late 1970s, lung cancers with or without asbestosis were found among asbestos workers. All cohort studies on asbestos workers and on chrysotile miners in China showed excess deaths from lung cancer. In a large scale of cohort study on asbestos workers, a synergistic effect was found between cigarette smoking and asbestos exposure in the production of lung cancer. There have been not so many cases of malignant mesotheliomas reported, so far. In the cohort of chrysotile miners, 4 cases of pleural mesothelioma were observed. In the large scale of cohort study on asbestos workers in 9 factories using only chrysotile only one case of pleural mesothelioma was detected for 10 years' observation. In another 2 cohort studies, 2 cases of peritoneal mesotheliomas were found, one in Shanghai asbestos factory where a small amount of crocidolite had been used in 1960s, and one in Anqing asbestos factory that was located near tremolite mine. Further study is needed especially for the relationship between exposure to Chinese chrysotile and malignant mesotheliomas.

Asbestos-related lung cancer and mesothelioma in Japan

In Japan, crocidolite had been used for asbestos cement pipe and spraying, and amosite had been used for building board and spraying. These two types of asbestos had stopped to use in Japan in the late 1970s. An extreme increase in imported asbestos (all 3 commercial types) was observed between 1960 and 1974. In 1960, 77,000 tons of asbestos were imported, and reached the peak as 352,316 tons in 1974. This extreme rise of asbestos imports corresponds with the recent rapid increase in mortality of malignant pleural mesothelioma. Between 1995 and 1999, an estimated mean annual death from pleural mesothelioma was about 500. The annual number of compensated occupational respiratory cancers due to asbestos exposure has also been increasing. Up to the end of March 2000, 162 cases with malignant mesothelioma and 197 cases with lung cancer were compensated. As for lung cancer, epidemiological studies are scanty in Japan. Limited environmental data of the working places in asbestos textile factories suggests that heavy asbestos exposure in the past made deaths from respiratory diseases. Less asbestos exposure will enable exposed workers to survive enough to reach cancer age. Even now smoking rate among males in Japan are over 50%. So lung cancer deaths caused by the interaction between smoking and asbestos exposure will be continuing.

The chemiluminescent response from human monocyte-derived macrophages exposed to various mineral fibers of different sizes

The aims of the present work were to quantify ability to induce lucigenin-dependent chemiluminescence (CL) from 6-9 day-old human monocyte-derived macrophages exposed to various mineral fibers, and to examine the relationship between ability to induce CL and fiber size. All fiber samples induced the CL response from the cells. The relationship between the number of fibers administered and the CL response was examined on all fiber samples by linear regression. The slope of the regression line supplies an approximation of the ability to induce CL. A strong increased correlation between geometric-mean length of fibers and ability to induce CL was observed for the seven fiber samples more than 6 microns in length (r = 0.9895). Geometric-mean width and the ability to induce CL showed no correlation. However, among the two fiber samples having a similar length distribution (RF2, RF3), the wider width sample (RF3, 2.4 microns) demonstrated lower ability to induce the CL than the narrower width sample (RF2, 1.1 microns). The present method enabled comparison of ability to induce lucigenin-dependent CL from human monocyte-derived macrophages for various mineral fibers with different sizes. Our findings suggested the possibility that ability to induce O2- production increased with fiber length, when fibers are longer than approximately 6 microns.

The prevalence of pleural plaques and/or pulmonary changes among construction workers in Okayama, Japan

BACKGROUND

Since asbestos has been widely used in Japanese building materials since 1960s, a large number of Japanese construction workers may be exposed to asbestos occupationally.

METHODS

Among 2951 construction workers in Okayama, Japan, the prevalence of asbestos-induced pleural or pulmonary changes was examined by screening chest x-rays; these findings were confirmed by computed tomography (CT) scanning of the chest.

RESULTS

Among 2951 construction workers, 168 (5.7%) were found to have significant findings for pleural plaque or pulmonary changes on chest x-ray. Seventy-four had both pleural plaque and asbestosis, 85 pleural plaques alone, and 9 asbestosis alone. In 11 subjects, pleural plaques were suggested by chest x-ray, but neither pleural plaque nor asbestosis was demonstrated by chest CT. Honeycombing as one of the characteristic findings of asbestosis was found in 29 subjects. Others showed subpleural spots or curvilinear shadow, which suggested the early stage of asbestosis. The occupations of these workers were carpenters (64), plasterers (27), and concrete board cutters (14). About 30% of the workers with these findings were aware that they were handling asbestos in activities such as installation of asbestos boards, and/or asbestos spraying.

CONCLUSIONS

As the incidence of malignant mesothelioma and primary lung cancer associated with asbestos exposure are high, screening by chest CT is necessary for detecting asbestos-induced pulmonary and/or pleural lesions. Education for protection such as telling about the presence of asbestos in building materials is also necessary.

Hepatic tumor rupture following effectual treatment with irinotecan in a patient with highly refractory malignant lymphoma

We describe a patient with highly refractory malignant lymphoma who died of hepatic tumor rupture following treatment with irinotecan (CPT-11). This 60-year-old man with non-Hodgkin's lymphoma (diffuse large B-cell lymphoma) demonstrated disease recurrence in the liver and the vertebrae following high-dose chemotherapy and autologous hematopoietic stem cell transfusion. He was treated with CPT-11 at a dose of one third of the conventional dose used for non-Hodgkin's lymphoma in Japan. The tumor in the liver markedly decreased in size but then ruptured. Although pathologic hepatic tumor rupture is a rare complication in patients with malignant lymphoma of the liver, this case demonstrates that hepatic tumor rupture may occur in refractory malignant lymphomas that reveal extensive degradation by this new, effective salvage therapy.

Clinical, pathological and mineralogical features in two autopsy cases of workers exposed to agalmatolite dust

An agalmatolite miner and processor showed large shadows at the bilateral hila accompanied by surrounding emphysematous changes and irregular shadows on chest X-ray films. Chest CT scans were characterized by a mixture of tiny irregular structures and small round opacities. Histopathological examination revealed massive fibrosis, which corresponded to large shadows, but only a small number of typical silicotic nodules, indicating mixed dust pneumoconiosis. Mineralogical examination of the autopsy lungs showed quartz, pyrophyllite, mica, and kaolinite. Quartz accounted for 70% of the amount of all mineral dust in both patients, but pyrophyllite accounted for 10.8% and 14.4%. The pulmonary mineral dust composition in the two patients was well consistent with the mineral composition of the raw clays in the agalmatolite mine. In the two patients, chest X-ray findings and histopathological findings of the lungs also suggested agalmatolite pneumoconiosis, which was confirmed by mineral analysis of the lungs.

A retrospective cohort study of male workers exposed to PVA fibers

In order to ascertain whether PVA fibers can produce cancer in humans or not, we have conducted a retrospective cohort study of workers exposed to PVA fibers. A total of 447 exposed and 2416 non-exposed male workers who were engaged before 1980 were followed up until the end of 1996. The SMR for all causes was 0.57 (observed 38, 95% CI: 0.41-0.78) for the exposed, and 0.66 (observed 210, 95% CI: 0.58-0.75). As for lung cancer, its SMR was 0.77 (observed 3, 95% CI: 0.15-2.24) for the exposed workers and 0.67 (12 observed, 95% CI: 0.34-1.16) for the non-exposed workers. Lung cancer SMR was 0.86 (observed 2, 95% CI: 0.10-3.11) for the workers with 20 or more years' employment. This study showed no difference in lung cancer risk between the workers exposed to PVA fibers and the non-exposed workers.

Anthophyllite exposure and endemic pleural plaques in Kumamoto, Japan

OBJECTIVES

This study explored the high prevalence of pleural plaques in the town of Matsubase in Kumamoto, Japan.

METHODS

Small-size chest X-ray film was used for screening, and all persons with pleural plaques were confirmed by computed tomography (CT). The prevalence rate of pleural plaques in the 4 districts of Matsubase and its surrounding towns and cities were also examined. The age-adjusted mortality rate for lung cancer in this town was compared with that of its surrounding towns and cities.

RESULTS

Pleural plaques were found in 1357 persons (724 men and 633 women) among the inhabitants who were more than 20 years of age in Matsubase between 1988 and 1993. CT scans ascertained 938 cases with pleural plaques among the 11 14 persons who participated. Thus at least 9.5% of the inhabitants over 20 years of age in this town had pleural plaques. The neighboring towns had a higher rate than the more distant towns. A large-scale open-cast asbestos mine and mill had been in operation in Matsubase between 1883 and 1970. Mineral analysis revealed anthophyllite fibers. Most of the plaques were found in persons who had never worked in the mine or mill.

CONCLUSIONS

The high prevalence of pleural plaques in Matsubase was due to anthophyllite exposure, mainly environmental. No mesotheliomas were found, however. These findings agree with those from an earlier study from Finland.

Spectroscopic properties of Nd 3 + and Pr 3 + in gallate glasses with low phonon energies

Absorption and fluorescence spectra of Nd3 +were measured in potassium tantalum gallate, lead bismuth gallate (PBG), fluorozirconate (ZBLAN), and Ge-Ga-S glasses. A Judd -Ofelt analysis was performed to determine the spontaneous emission probability and stimulated emission cross section of the4 F3/2 ?4 I11/2 transition of Nd3 +. Raman spectra were studied to clarify the maximum phonon energies of the glasses. The fluorescence of the1 G4?3 H5 transition of Pr3 + in a dehydrated PBG glass was observed for the first time to our knowledge. The PBG glass has a higher quantum efficiency than that of ZBLAN glass based on the Judd -Ofelt analysis.

A new approach for acute embolus occlusion of the superior mesenteric artery

Acute embolus occlusion of the superior mesenteric artery (SMA) either demonstrates a poor prognosis, or forces the patients to endure miserable postoperative dietary lives. Recently, we developed a new successful technique which reduced the length of the intestinal segment that had to be removed. The technique was as follows: (1) the distal end of the SMA was ligated to avoid perfusion of the necrotic segment, and (2) a Fogarty balloon catheter was inserted from the distal end of the SMA and then passed proximally to remove any remaining clots. Using the above-described technique on 3 cases from 1992 to 1994, we were thus able to shorten the length of the intestine that had to be removed and thereby greatly improve the patients' postoperative dietary lives.

Effect of poling conditions on second-harmonic generation in fused silica

A systematic study of the effects of poling time and applied voltage on second-harmonic (SH) generation in thermally poled silica glass reveals that the SH signal is proportional to the square of the applied voltage and that the speed of the poling process increases with the applied voltage. Prior treatment of the samples is found to affect the poling process, and the optimum poling conditions are observed to depend on the poling atmosphere. The mechanism of thermal poling is discussed in the light of these new results.

[A case report of small cell carcinoma of the esophagus with remarkable response to neoadjuvant chemotherapy]

A 61-year-old male consulted our hospital with complaints of pain in swallowing. The X-ray Barium studies and upper gastrointestinal (UGI) scope revealed an irregular ulcerated lesion in the middle portion of the esophagus. He was diagnosed as having small cell carcinoma of the esophagus by means of biopsy specimens. Three courses of combined chemotherapy with CDDP, etoposide and 5-FU were used before operation. Following the chemotherapy, according to the UGI scope findings, the tumor of the esophagus disappeared. An esophagectomy through a thoracolaparotomy was performed. The chemotherapy resulted in a Grade 2 response, as ascertained by means of pathological findings for the resected specimen. After an additional course of chemotherapy, the patient was discharged from the hospital. Although we performed the curative resection for this patient, extensive recurrences and distant metastasis to the mediastinal lymph nodes and lung were found in less than a year. It is said that this tumor has a poor prognosis, and the one-year survival rate is about 10% following the treatment. It is necessary to combine surgery with effective chemotherapy and irradiation to obtain a good prognosis after resection of small cell carcinoma of the esophagus.

Treatment of large liver cyst evaluated with CA 19-9 in the cystic fluid

A middle-aged woman was admitted with a diagnosis of liver cysts. The patient was symptomatic and was treated by injecting absolute ethanol into the largest cyst every week, but the secretion from the cyst persisted. The patient was then treated by absolute ethanol injection every day with good results. CA 19-9 was measured in the cystic fluid. The secretion was related to CA 19-9 activity. Thus, for patients with symptoms from a liver cyst, the injection of ethanol every day can be effective. CA 19-9 level in the contents of the liver cyst was an important factor in assessing the effect of ethanol injection on the liver cyst.

[Therapeutic effect of a mineralocorticoid in patients with hyponatremia of central origin]

Patients with hyponatremia of central origin were treated with a mineralocorticoid, and the therapeutic effect assessed. The subjects of this study were 14 patients (5 with subarachnoid hemorrhage, 2 with hypertensive intracerebral hemorrhage and 7 with head injury) who developed hyponatremia as a complication during their hospital stay for treatment of their intracranial lesions between March 1993 and April 1994. Hyponatremia of central origin was defined as serum Na+ levels below 135 mEq/l for at least two consecutive days with no other discernible etiology. The mineralocorticoid used was fludrocortisone acetate, and as a rule administration was started the day after the onset of hyponatremia. The mean interval until the onset of hyponatremia was 7.5 days, and the mean minimum serum sodium level was 125.7 mEq/l. The dose of fludrocortisone was 0.3 congruent to 0.6 mg/day, the mean period of administration 5.8 days, and route was via a stomach tube in 3 cases and by mouth in 11 cases. The therapeutic effect was good (improvement within 5 days) in 11 cases and fair (improvement in 5 to 8 days) in 3 cases. None of the patients manifested side effects. All of the patients had lower urinary sodium excretion than before administration, with the mean rate of decrease of 66.9%. Mineralocorticoids, which suppress natriuresis, are safe and effective in the treatment of hyponatremia of central origin. It appears that mineralocorticoid therapy may be aggressively tried in severe cases in which NaCl loading is ineffective.

A novel therapy for internal hemorrhoids: ligation of the hemorrhoidal artery with a newly devised instrument (Moricorn) in conjunction with a Doppler flowmeter

OBJECTIVES

To assess the usefulness of hemorrhoidal artery ligation (HAL) for internal hemorrhoids with a newly devised instrument (the Moricorn).

METHODS

We devised a new instrument (the Moricorn) that is used in conjunction with a Doppler flowmeter. This instrument allows for easy and safe ligation of the hemorrhoidal artery. HAL with the Moricorn was performed on 116 patients with internal hemorrhoids who had episodes of anal pain, bleeding, and prolapse. One month after treatment, the effect was evaluated on the basis of improvement of symptoms and the shrinkage of hemorrhoidal tissue.

RESULTS

The treatment's effect was observed in 50 of 52 patients (96%) with pain, 50 of 64 (78%) with prolapse, and 92 of 96 (95%) with bleeding. No patient required anesthesia throughout the entire procedure. No major complications were encountered with this treatment.

CONCLUSIONS

HAL with the Moricorn is a simple, safe, and effective method. However, further observations predicated on a longer follow-up, a larger number of patients, and comparisons with other conventional treatments are called for.

[Subacute subdural hematoma: findings in CT, MRI and operations and review of onset mechanism]

Subacute subdural hematoma was investigated in terms of findings in CT, MRI and operations and of onset mechanism. The subjects were 7 cases of subacute subdural hematoma in which CT and MRI were performed during the past 5 year period. Subacute subdural hematoma here was defined as a nonoperated case with acute subdural hematoma, accompanied by subacute exacerbation 1-3 weeks after head trauma. The time from the injury to the onset averaged 13.7 days. CT revealed mixed density in 4 cases, low density in 3 cases and cerebral atrophy in all cases, with increasing mass sign due to the enlarged low density area. MRI revealed mixed intensity in 5 cases and high intensity in 2 cases, with increasing mass sign due to the enlarged high intensity area. Operation disclosed the outer membrane of the hematoma only in 1 case, but the inner membrane could not be identified in any case. Analysis of the hematoma contents showed a low hemoglobin concentrations and a high level of methemoglobin. Lack of outer membrane in cases with subacute subdural hematoma suggests that this is a different disease entity from chronic subdural hematoma. It is surmised that subacute subdural hematoma is the result of subdural effusion in the subacute stage, because, judging from the findings of CT and MRI each performed over time, cerebrospinal fluid is considered accountable for the increase in the mass sign.

[Therapeutic effect of mineralocorticoid in patients with hyponatremia of central origin]

Patients with hyponatremia of central origin were treated with a mineralocorticoid, and the pathogenetic mechanism of the hyponatremia was assessed based on the therapeutic effect obtained. The subjects were 14 patients (6 with subarachnoid hemorrhage, 3 with hypertensive intracerebral hemorrhage, 2 with cerebral infarct and 3 with head injury) who developed hyponatremia, as a complication during their hospital stay for their intracranial lesions from April to December 1992. Patients with serum Na levels below 135 mEq/l for more than 2 days with no other discernible etiology were defined as having hyponatremia of central origin. The mineralocorticoid used was fludrocortisone acetate, and as a rule administration was started the day after the onset of hyponatremia. When improvements occurred within 3 days, in 3 to 7 days, or 8 days or more efficacy was rated "excellent", "good" or "poor", respectively. The mean interval until the onset of hyponatremia was 10.4 days, its mean duration was 5.7 days, and the mean minimum serum sodium level was 129.5 mEq/l. The dose of fludrocortisone administration was 0.1 mg/day except for one patient who was treated with 0.3 mg/day. The mean period of administration was 3.7 days (range: 3 to 6 days), and the route was via a stomach tube in 5 cases and oral in 9 cases. The therapeutic effect was excellent in 9 cases, good in 3 cases and poor in 2 cases, the efficacy rate being 86%. None of the patients manifested side effects. Plasma atrial natriuretic peptide levels were above 100 pg/ml in 2 patients and 50-100 pg/ml in 8 patients and neither of the former 2 patients exhibited "excellent" efficacy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Subacute subdural hematoma--reexamination of mechanism by CT and MRI findings]

We have already reported about the importance of establishing the concept of subacute subdural hematoma. But the mechanism by which this disease develops has not as yet been elucidated fully. In one case of subacute subdural hematoma, we were able to perform CT and MRI over time and obtained findings which were of use in studying the mechanism of development. The case was a 56-year-old male. He developed with seizure. CT on admission revealed acute subdural hematoma and subarachnoid hemorrhage. But neurological deficits were absent. So he was treated conservatively. On the 16th hospital day there appeared seizure, anisocoria and an increase in the mass sign due to subdural hematoma was noted on CT, so a diagnosis of subacute subdural hematoma was made. Cerebrospinal fluid was considered accountable for the increase in the mass sign judging from the findings of CT and MRI each performed over time. It was surmised that subdural effusion developed concurrently in the subacute stage. Three conditions, namely, presence of (1) arachnoid tear, (2) clots, (3) no intracranial hypertension are considered important as the mechanism by which subacute subdural hematoma develops.

[A study of plasma atrial natriuretic peptide, antidiuretic hormone and cerebral vasospasms in patients with aneurysmal subarachnoid hemorrhage]

The relationship between plasma atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) both of which show high values after subarachnoid hemorrhage and cerebral vasospasm was studied. The subjects were 23 patients who were admitted because of aneurysmal subarachnoid hemorrhage during three years from March, 1989 to March, 1992 and in whom plasma ANP and ADH levels could be determined over time. Cerebral vasospasm was evaluated by the finding of cerebral angiography, clinical symptoms, and presence or not of low density areas on CT. Hyponatremia was defined as the serum sodium level of 130 mEq/l or less for two days or more. Angiographical vasospasm was found in 17 patients (85%), symptomatic vasospasm in 15 patients (65.2%), low density areas on CT in 9 patients (40.9%) and hyponatremia in 8 patients (34.8%). Symptomatic vasospasm was noted in 7 of the 8 patients (87.5%) with hyponatremia, low density areas on CT in 4 patients (50%), the detection rate being high. The plasma ANP and ADH levels were 76.7 +/- 32.1 pg/ml and 2.2 +/- 0.7 pg/ml respectively in the patients with symptomatic vasospasm against 38.3 +/- 21.3 pg/ml and 2.4 +/- 0.6 pg/ml respectively without symptomatic vasospasm, the plasma ANP level being significantly high in the patients with symptomatic vasospasm (p < 0.01). The plasma ANP and ADH were 71.2 +/- 33.8 pg/ml and 2.0 +/- 1.1 pg/ml respectively in the patients with low density areas on CT against 51.2 +/- 31.3 pg/ml and 1.8 +/- 0.5 pg/ml respectively without low density areas on CT.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hyponatremia and cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage]

We studied retrospectively the relationship between hyponatremia and cerebral vasospasm in 121 consecutive patients with aneurysmal subarachnoid hemorrhage. In 19 patients sodium levels fell below 130 mEq/l on at least two consecutive days. Hyponatremia developed at average 8.9 hospital day and lasted for 4.4 days. It was mild (126 to 130 mEq/l) in 15 patients, moderate (121 to 125 mEq/l) in 3 patients, and severe (116 to 120 mEq/l) in 1 patient. Cerebral vasospasm was evaluated by angiography, symptoms and CT finding. Angiographical vasospasm was found in 57 patients, symptomatic vasospasm in 38 patients and low density area on CT in 20 patients. Angiographical vasospasm developed in 15 of the 19 patients (78.9%) with hyponatremia, symptomatic vasospasm in 16 patients (84.2%), low density area on CT in 8 patients (42.1%), the difference being significantly high. (respectively, p < 0.01, p < 0.001 and p < 0.01 by chi-square test) Polyuria of 2500 ml or more immediately before the onset of hyponatremia developed in 14 patients (87.5%). When symptomatic vasospasm and hyponatremia coincided, there were only 4 patients in which symptomatic vasospasm was preceded by hyponatremia. So, it is difficult to predict the development of vasospasm from that of hyponatremia. This study found incidence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage to be significantly higher in patients who developed hyponatremia, which raised suspicion about the presence of dehydration. Hyponatremia with central origin generally remains asymptomatic, but it is important to treat positively when the pathology of cerebral vasospasm is taken into consideration.

[A study of plasma atrial natriuretic peptide, antidiuretic hormone and aldosterone levels in a series of patients with intracranial disease and hyponatremia]

For intracranial diseases, plasma atrial natriuretic peptide (ANP), antidiuretic hormone (ADH) and aldosterone were determined and their effects on the development of hyponatremia with central origin were studied. The subjects were 71 cases of intracranial diseases which were admitted to our hospital during a period of 1 year from March, 1989 to March, 1990. The diseases were broken down to subarachnoid hemorrhage 26 cases, hypertensive intracerebral hemorrhage 19 cases, head injury 12 cases, cerebral infarction 11 cases and 3 other cases. Serum-urine electrolytes, plasma ANP and ADH were determined in the acute stage on Day 1 to 4, in the hyponatremia stage on Day 5 to 14 and in the chronic stage on Day 15 downward. Hyponatremia was defined as the serum sodium level of 130 mEq/l or less. Cases evidently having other causes such as heart failure and renal insufficiency were excluded. In the normal control group of persons who were admitted to our hospital for a close checkup (n = 20), plasma ANP was 26.5 +/- 11.6 pg/ml (10-50); levels of 50 pg/ml or more were regarded as abnormally high. 1) Hyponatremia was found in 18 cases (25.4%), subarachnoid hemorrhage in 7 cases, hypertensive intracerebral hemorrhage in 4 cases, head injury in 5 cases and others in 2 cases. 2) The time of onset of hyponatremia was on the 8.3 hospital day. The duration was 7.2 days. The minimum serum sodium level was 124.6 mEq/l. 3) There was no significant change in the plasma aldosterone level at each stage.2+ Predicting development of hyponatremia from plasma ADH and ANP levels in the acute stage is difficult. Inadequate secretion of ANP rather than ADH appeared to be an important factor for the development of hyponatremia, but the plasma ANP level was not always abnormally high, so involvement of other sodium diuretic factors should also be kept in mind.

[CT and 123I-IMP SPECT findings of head injuries with hyponatremia]

CT and SPECT findings were examined and the relationship between development of hyponatremia and lesions was studied in cases who developed hyponatremia following head injury. Six cases of hyponatremia after head injury in the last two years were used as the subjects. SPECT was performed by the 123I-IMP intravenous injection method using Tomomatic 64. Slice 2 of 4 to 6 cm on the OM line in the early image was used as the subject site. The data of development of hyponatremia was 5.8 patients days, duration 9.2 days, minimum serum Na level 117.2 mEq/l and minimum plasma osmotic pressure 247.6 mOsm/lH2O. CT findings in the hyponatremic stage showed frontal subdural effusion in all the cases. SPECT findings revealed a decrease of CBF in the frontal region on both sides and in the central region. CBF in the central region also tended to improve at a time when hyponatremia improved. In hyponatremia after head injury, lesions are often found in the frontal region on CT, and CBF in the central region is also decreased bilaterally on SPECT, which is presumed to be concerned with the development of hyponatremia.

[Internal carotid artery stenosis and external carotid artery occlusion with unusual extracranial collateral pathway: case report]

A patient with stenosis of the internal carotid artery and occlusion of the external carotid artery associated with an unusual extracranial collateral pathway is presented. A 63-year-old man was hospitalized for sudden onset of black-out after urination. He was alert, and no neurological deficit was found. MRI showed multiple lacunae in the bilateral putamens. Cerebral angiogram demonstrated severe stenosis of the left internal carotid artery at its cervical segment and complete occlusion of the left external carotid artery at its origin. The ascending pharyngeal artery originated from the left internal carotid artery above its stenotic lesion and the superior thyroid artery originated from the left common carotid artery. The sternocleidomastoid branch from the left superior thyroid artery and the muscular branch from the left vertebral artery anastomosed with the muscular branch of the ascending pharyngeal artery. The ascending pharyngeal artery maintained patency of the internal carotid artery. It is important to perform vertebral angiography when there is proximal occlusion and severe stenosis of the internal carotid artery, and when the ascending pharyngeal artery has not been clearly identified as a branch from the ipsilateral external carotid artery on the common carotid angiogram.

[A retrospective cohort study of workers in small asbestos industries in south Osaka]

A retrospective cohort study was carried out on asbestos workers who had received health examinations in 1972 to 1974 conducted by the Osaka Health Center. The subjects, total of 789 (329 males, 460 females) were followed-up for 10 years (Jan. 1, 1975-Dec. 31, 1984). There were sixty-one deaths in the cohort--4 tuberculosis, 12 malignant neoplasms (4 stomach cancers, 8 respiratory cancers including one case of pleural mesothelioma), 18 circulatory diseases, 24 respiratory diseases, and 3 other causes of death. Standardized mortality ratio (SMR) was calculated age and sex-specific death rates for the general population in Osaka between 1975-79 and 1980-84. SMR for all causes of death, stomach cancer, respiratory cancer, circulatory diseases, and respiratory diseases were 1.15, 3.29, 0.75, 3.88, 0.93 and 8.63 respectively. Respiratory cancer and respiratory diseases showed statistically significant (p less than 0.01) excess death with a mean death age of 59 and 56 years old respectively.

Early asbestosis: evaluation with high-resolution CT

To determine the earliest stage at which lesions in asbestosis can be diagnosed and to assess their progression, 23 asbestos-exposed patients with minimal or no abnormalities at plain radiography were examined with high-resolution computed tomography (HRCT) twice, with an interval of 12-37 months between examinations. In 21 of the patients, parenchymal abnormalities were found. Major parenchymal features seen at CT included thickened intralobular and interlobular lines, subpleural curvilinear lines, pleural-based nodular irregularities, hazy patches of increased attenuation, small cystic spaces, and small areas of low attenuation. At paired serial CT, subpleural isolated dots or branching structures connected with the most peripheral branch of the pulmonary artery started to appear in lower subpleural zones and then became confluent to create pleural-based nodular irregularities. CT-pathologic correlation led to the conclusion that the confluence of subpleural peribronchiolar fibrosis creates subpleural fibrosis.