Deep learning-based reconstruction for acceleration of lumbar spine MRI: a prospective comparison with standard MRI

OBJECTIVE

To compare the image quality and diagnostic performance between standard turbo spin-echo MRI and accelerated MRI with deep learning (DL)-based image reconstruction for degenerative lumbar spine diseases.

MATERIALS AND METHODS

Fifty patients who underwent both the standard and accelerated lumbar MRIs at a 1.5-T scanner for degenerative lumbar spine diseases were prospectively enrolled. DL reconstruction algorithm generated coarse (DL_coarse) and fine (DL_fine) images from the accelerated protocol. Image quality was quantitatively assessed in terms of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) and qualitatively assessed using five-point visual scoring systems. The sensitivity and specificity of four radiologists for the diagnosis of degenerative diseases in both protocols were compared.

RESULTS

The accelerated protocol reduced the average MRI acquisition time by 32.3% as compared to the standard protocol. As compared with standard images, DL_coarse and DL_fine showed significantly higher SNRs on T1-weighted images (T1WI; both p < .001) and T2-weighted images (T2WI; p = .002 and p < 0.001), higher CNRs on T1WI (both p < 0.001), and similar CNRs on T2WI (p = .49 and p = .27). The average radiologist assessment of overall image quality for DL_coarse and DL_fine was higher on sagittal T1WI (p = .04 and p < .001) and axial T2WI (p = .006 and p = .01) and similar on sagittal T2WI (p = .90 and p = .91). Both DL_coarse and DL_fine had better image quality of cauda equina and paraspinal muscles on axial T2WI (both p = .04 for cauda equina; p = .008 and p = .002 for paraspinal muscles). Differences in sensitivity and specificity for the detection of central canal stenosis and neural foraminal stenosis between standard and DL-reconstructed images were all statistically nonsignificant (p ≥ 0.05).

CONCLUSION

DL-based protocol reduced MRI acquisition time without degrading image quality and diagnostic performance of readers for degenerative lumbar spine diseases.

CLINICAL RELEVANCE STATEMENT

The deep learning (DL)-based reconstruction algorithm may be used to further accelerate spine MRI imaging to reduce patient discomfort and increase the cost efficiency of spine MRI imaging.

KEY POINTS

• By using deep learning (DL)-based reconstruction algorithm in combination with the accelerated MRI protocol, the average acquisition time was reduced by 32.3% as compared with the standard protocol. • DL-reconstructed images had similar or better quantitative/qualitative overall image quality and similar or better image quality for the delineation of most individual anatomical structures. • The average radiologist's sensitivity and specificity for the detection of major degenerative lumbar spine diseases, including central canal stenosis, neural foraminal stenosis, and disc herniation, on standard and DL-reconstructed images, were similar.

Deep learning-based reconstruction of virtual monoenergetic images of kVp-switching dual energy CT for evaluation of hypervascular liver lesions: Comparison with standard reconstruction technique

OBJECTIVE

To investigate clinical applicability of deep learning(DL)-based reconstruction of virtual monoenergetic images(VMIs) of arterial phase liver CT obtained by rapid kVp-switching dual-energy CT for evaluation of hypervascular liver lesions.

MATERIALS AND METHODS

We retrospectively included 109 patients who had available late arterial phase liver CT images of the liver obtained with a rapid switching kVp DECT scanner for suspicious intra-abdominal malignancies. Two VMIs of 70 keV and 40 keV were reconstructed using adaptive statistical iterative reconstruction (ASiR-V) for arterial phase scans. VMIs at 40 keV were additionally reconstructed with a vendor-agnostic DL-based reconstruction technique (ClariCT.AI, ClariPi, DL 40 keV). Qualitative, quantitative image quality and subjective diagnostic acceptability were compared according to reconstruction techniques.

RESULTS

In qualitative analysis, DL 40 keV images showed less image noise (4.55 vs 3.11 vs 3.95, p < 0.001), better image sharpness (4.75 vs 4.16 vs 4.3, p < 0.001), better image contrast (4.98 vs 4.72 vs 4.19, p < 0.017), better lesion conspicuity (4.61 vs 4.23 vs 3.4, p < 0.001) and diagnostic acceptability (4.59 vs 3.88 vs 4.09, p < 0.001) compared with ASiR-V 40 keV or 70 keV image sets. In quantitative analysis, DL 40 keV significantly reduced image noise relative to ASiR-V 40 keV images (49.9%, p < 0.001) and ASiR-V 70 keV images (85.2%, p = 0.012). DL 40 keV images showed significantly higher CNR_{lesion to the liver} and SNR_liver than ASiR-V 40 keV image and 70 keV images (p < 0.001).

CONCLUSION

DL-based reconstruction of 40 keV images using vendor-agnostic software showed greater noise reduction, better lesion conspicuity, image contrast, image sharpness, and higher overall image diagnostic acceptability than ASiR for 40 keV or 70 keV images in patients with hypervascular liver lesions.

Deep Learning-Assisted Diagnosis of Pediatric Skull Fractures on Plain Radiographs

Objective

To develop and evaluate a deep learning-based artificial intelligence (AI) model for detecting skull fractures on plain radiographs in children.

Materials and Methods

This retrospective multi-center study consisted of a development dataset acquired from two hospitals (n = 149 and 264) and an external test set (n = 95) from a third hospital. Datasets included children with head trauma who underwent both skull radiography and cranial computed tomography (CT). The development dataset was split into training, tuning, and internal test sets in a ratio of 7:1:2. The reference standard for skull fracture was cranial CT. Two radiology residents, a pediatric radiologist, and two emergency physicians participated in a two-session observer study on an external test set with and without AI assistance. We obtained the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity along with their 95% confidence intervals (CIs).

Results

The AI model showed an AUROC of 0.922 (95% CI, 0.842–0.969) in the internal test set and 0.870 (95% CI, 0.785–0.930) in the external test set. The model had a sensitivity of 81.1% (95% CI, 64.8%–92.0%) and specificity of 91.3% (95% CI, 79.2%–97.6%) for the internal test set and 78.9% (95% CI, 54.4%–93.9%) and 88.2% (95% CI, 78.7%–94.4%), respectively, for the external test set. With the model’s assistance, significant AUROC improvement was observed in radiology residents (pooled results) and emergency physicians (pooled results) with the difference from reading without AI assistance of 0.094 (95% CI, 0.020–0.168; p = 0.012) and 0.069 (95% CI, 0.002–0.136; p = 0.043), respectively, but not in the pediatric radiologist with the difference of 0.008 (95% CI, -0.074–0.090; p = 0.850).

Conclusion

A deep learning-based AI model improved the performance of inexperienced radiologists and emergency physicians in diagnosing pediatric skull fractures on plain radiographs.

6112Usefulness of the trans-stent fractional flow reserve gradient for predicting clinical outcomes

Aims

The clinical meaning of a trans-stent pressure gradient after DES implantation has not been estimated adequately. We evaluated the usefulness of a fractional flow reserve (FFR) gradient across the stent (ΔFFRstent) for long-term clinical outcomes after percutaneous coronary intervention (PCI) with a drug-eluting stent (DES).

Methods and results

FFR pull-back and intravascular ultrasound (IVUS) were performed after successful PCI in 135 left anterior descending artery lesions. ΔFFRstent was defined as the FFR gradient across the stent. The ΔFFRstent/length was defined as the ΔFFRstent value divided by the total stent length multiplied by 10 [= (ΔFFRstent ÷ stent length) x 10]. Major adverse cardiac events (MACEs) were the composite of all-cause death, target vessel related myocardial infarction, and target lesion revascularisation. Despite successful PCI without significant complications on IVUS, ΔFFRstent >0 was observed in 98.5% of cases. ΔFFRstent ≥0.04 and ΔFFRstent/length ≥0.009 predicted suboptimal stenting defined as final minimal stent area <5.5 mm2. During 2183±898 days, the MACE-free survival rate was significantly lower in patients with ΔFFRstent ≥0.04 and ΔFFRstent/length ≥0.009 compared to those with lower values (69.6 vs. 93.4%, log-rank p=0.031; 72.1 vs. 97.7%, log-rank p=0.003, respectively). ΔFFRstent/length ≥0.009 (hazard ratio 10.1, p=0.032) was an independent predictor of MACE.

Trans-stent FFR and MACE

Conclusion

A trans-stent FFR gradient was frequently observed in DES-treated patients despite successful PCI results. ΔFFRstent and ΔFFRstent/length are useful indicators for optimising a DES and are related to long-term outcomes.

Expansion microscopy

Super-resolution optical microscopy techniques have revolutionized how we see and understand biology. In recent past, a new super-resolution optical microscopy technique called expansion microscopy (ExM) was developed. Unlike other pre-existing super-resolution imaging techniques, this technique achieves super-resolution by physically expanding biological specimens via a swellable hydrogel. After the development of ExM, various techniques based on ExM but with improved performance in various aspects, have been developed. In this review, we introduce the basic principles of ExM and its variants. and compare the advantages and disadvantages of these techniques. In addition, we present the applications of ExM techniques in various fields.

First-Line Use of Core Needle Biopsy for High-Yield Preliminary Diagnosis of Thyroid Nodules

BACKGROUND AND PURPOSE

Although core needle biopsy was introduced as a diagnostic alternative to fine-needle aspiration, the utility and safety of core needle biopsy for thyroid nodules in a large population has yet to be studied comprehensively. We evaluate core needle biopsy yields on a large-scale basis to investigate its potential in the preliminary diagnosis of thyroid nodules.

MATERIALS AND METHODS

Between March 2005 and December 2013, 2448 initially detected thyroid nodules from 2120 consecutive patients who underwent core needle biopsy were retrospectively evaluated. Of these, 72 thyroid nodules from 63 patients were excluded due to prior fine-needle aspiration attempts. The inconclusive and conclusive result rates, diagnostic accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and unnecessary surgery rate of core needle biopsy were evaluated.

RESULTS

With core needle biopsy as the first-line method, the inconclusive result rate was 11.9% (283/2376) and the conclusive result rate was 88.1% (2093/2376). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of core needle biopsy for the diagnosis of malignancy were 96.7% (1160/1200), 89.7% (347/387), 100% (813/813), 100% (347/347), and 95.3% (813/853), respectively. There were no major complications and 12 minor complications.

CONCLUSIONS

We have demonstrated that first-line use of core needle biopsy may well improve diagnostic accuracy in thyroid nodules, reducing inconclusive or false-negative results and unnecessary operations. Such benefits underscore the promising role of core needle biopsy in managing thyroid nodules and optimizing related surgical decision-making.

Performance evaluation of the new hematology analyzer Sysmex XN-series

INTRODUCTION

The Sysmex XN-series is a new automated hematology analyzer designed to improve the accuracy of cell counts and the specificity of the flagging events.

METHODS

The basic characteristics and the performance of new measurement channels of the XN were evaluated and compared with the Sysmex XE-2100 and the manual method. Fluorescent platelet count (PLT-F) was compared with the flow cytometric method. The low WBC mode and body fluid mode were also evaluated. For workflow analysis, 1005 samples were analyzed on both the XN and the XE-2100, and manual review rates were compared.

RESULTS

All parameters measured by the XN correlated well with the XE-2100. PLT-F showed better correlation with the flow cytometric method (r(2)  = 0.80) compared with optical platelet count (r(2)  = 0.73) for platelet counts <70 × 10(9) /L. The low WBC mode reported accurate leukocyte differentials for samples with a WBC count <0.5 × 10(9) /L. Relatively good correlation was found for WBC counts between the manual method and the body fluid mode (r = 0.88). The XN made less flags than the XE-2100, while the sensitivities of both instruments were comparable.

CONCLUSION

The XN provided reliable results on low cell counts, as well as reduced manual blood film reviews, while maintaining a proper level of diagnostic sensitivity.

Performance evaluation of the new hematology analyzer Sysmex XN-series

INTRODUCTION

The Sysmex XN-series is a new automated hematology analyzer designed to improve the accuracy of cell counts and the specificity of the flagging events.

METHODS

The basic characteristics and the performance of new measurement channels of the XN were evaluated and compared with the Sysmex XE-2100 and the manual method. Fluorescent platelet count (PLT-F) was compared with the flow cytometric method. The low WBC mode and body fluid mode were also evaluated. For workflow analysis, 1005 samples were analyzed on both the XN and the XE-2100, and manual review rates were compared.

RESULTS

All parameters measured by the XN correlated well with the XE-2100. PLT-F showed better correlation with the flow cytometric method (r(2)  = 0.80) compared with optical platelet count (r(2)  = 0.73) for platelet counts <70 × 10(9) /L. The low WBC mode reported accurate leukocyte differentials for samples with a WBC count <0.5 × 10(9) /L. Relatively good correlation was found for WBC counts between the manual method and the body fluid mode (r = 0.88). The XN made less flags than the XE-2100, while the sensitivities of both instruments were comparable.

CONCLUSION

The XN provided reliable results on low cell counts, as well as reduced manual blood film reviews, while maintaining a proper level of diagnostic sensitivity.

Codon-optimized expression of fish iridovirus capsid protein in yeast and its application as an oral vaccine candidate

Fish iridovirus causes systemic disease with high morbidity and mortality in various species of wild and farm-raised fish, resulting in severe economic losses. Recently, frequent outbreaks of iridovirus infection have occurred among cultured fish in many Asian countries, emphasizing the need for a protective vaccine programme or the development of a suitable therapy. In this study, we expressed a recombinant major capsid protein (rMCP) of rock bream iridovirus (RBIV) from yeast using codon optimization. The rMCP in yeast was added to feed in an attempt to induce intestinal mucosal immunity for protection against and/or to reduce the severity of fish iridovirus infection. We found that fish immunized orally with rMCP underwent a successful induction of antibodies (P < 0.05) and were protected (P = 0.0001) against viral challenge. Based upon these results, oral administration of immunogenic protein as an antigen can be considered a useful method for implementation of vaccine programmes against iridovirus as well as other marine viral diseases.

The effects of ErhBMP-2-/EGCG-coated BCP bone substitute on dehiscence around dental implants in dogs

OBJECTIVES

The purpose was to evaluate the effect of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2)-/epigallocatechin-3-gallate (EGCG)-coated biphasic calcium phosphate (BCP) and titanium barrier membrane on dehiscence defects in dogs.

MATERIALS AND METHODS

In five mongrel dogs, the dehiscence bony defects around dental implants were surgically created and in total three implants were placed at edentulous ridge of which teeth had been extracted 12 weeks before. For the control group, BCP was applied to the dehiscence defect. For experimental groups, ErhBMP-2-coated BCP and ErhBMP-2-/EGCG-coated BCP were applied. The newly designed titanium barrier membrane was used to apply all the defects. The defects were evaluated histologically and histometrically after 12 weeks. The comparative statistics of the groups were obtained through Kruskal-Wallis test.

RESULTS

In bone-to-implant contact (BIC), bone density (BD), bone regeneration height (BRH), and bone mineralization apposition rate (BMAR), differences among groups were not found. ErhBMP-2/EGCG group appeared to have higher value. In fluorescence analysis, bone remodeling around graft material was more active in the ErhBMP-2/EGCG group.

CONCLUSION

Within the limit of this study, it is reasonable to assume that BMP-2-/EGCG-coated biphasic BCP and the newly designed titanium membrane were more beneficial in dehiscence defect healing with increased bone remodeling.

Evaluation of overnight storage conditions for autologous peripheral blood stem cell products: comparison of three different conditions

BACKGROUND

Overnight (ON) storage of peripheral blood stem cell (PBSC) occurs frequently in clinical settings. However, there are no standard guidelines for optimal storage conditions of freshly harvested PBSC. The aim of this study was to investigate the influence of storage temperatures on the quality of autologous PBSC and establish optimal storage conditions before cryopreservation.

METHODS

A retrospective analysis was performed on 260 PBSC harvests according to pre-cryopreservation conditions: immediate processing or ON storage at room temperature (RT). For direct comparison, 30 autologous PBSC products were collected prospectively and prepared under three different pre-cryopreservation conditions: immediate processing, ON storage at 4°C and ON storage at RT. The recovery of CD34(+) cells, post-thaw CFU-GM count and viability were analysed.

RESULTS

Retrospective analysis revealed that post-thaw CFU-GM count was significantly lower when PBSC were stored ON at RT compared to when immediately processed (136·4 vs. 409·6/μl). Prospective analysis showed a mean recovery of CD34(+) cells of 65·5 ± 25·1%, 70·5 ± 27·4% and 35·9 ± 25·1% for immediate processing, ON storage at 4°C and ON storage at RT, respectively. Similarly, mean viability and CFU-GM counts were significantly reduced when stored ON at RT compared to when immediately processed or stored ON at 4°C (60·4 ± 25·6 vs. 84·1 ± 12·9 vs. 82·7 ± 12·6%, 15·7 ± 25·7 vs. 398·5 ± 906·2 vs. 350·0 ± 847·9/μl, respectively).

CONCLUSIONS

ON storage of autologous PBSC at RT significantly decreased the quality of HPCs. These data indicate that ON storage of autologous PBSC at 4°C would be the most reasonable approach for maintaining the quality of HPCs when immediate processing is not possible.

Blind oral endotracheal intubation of rats using a ventilator to verify correct placement

Endotracheal intubation in rats is challenging due to difficulties visualizing the epiglottis and vocal cords. No visualization of these structures results in repeated intubation attempts which can cause trauma to the oral cavity and/or oesophagus, and death of the animal due to respiratory failure. Here, we describe a simple blind oral tracheal intubation technique in the rat that decreases the frequency of repeated intubations using an intubation device that comprises a 16 G intravenous catheter and a modified 18 G epidural needle, and a rodent ventilator. The epidural needle is bent in such a way that it curves in conformity with the rat's oral airway in order to direct the catheter into the larynx, and the rodent ventilator is used to verify its correct placement. The first attempt success rate of endotracheal intubation using the blind oral tracheal intubation technique with a rodent ventilator was greater than the first attempt success rate using the blind oral tracheal intubation technique without using a rodent ventilator. Although this method is a simple modification of a previously described method of blind oral endotracheal intubation, our method is easy to learn, inexpensive and does not require specialized equipment.

Nitric oxide-induced IL-8 expression is mediated by NF-kappaB and AP-1 in gastric epithelial AGS cells

Inducible nitric oxide synthase (iNOS) and interleukin-8 (IL-8) mediate gastric inflammation. Nitric oxide (NO) produced by iNOS may activate oxidant-sensitive transcription factors. There are the binding sites for NF-kappaB, AP-1, and C/EBP (CCAAT/enhancer binding protein) in the promoter regions of IL-8 gene. The present study aims to investigate whether NO donors, SIN-1 and NOC-18, activate oxidant-sensitive transcription factors NF-kappaB and AP-1 as well as C/EBP to induce IL-8 expression in gastric epithelial AGS cells. Gastric epithelial AGS cells were treated with NO donors, SIN-1 and NOC-18. mRNA expression and protein level of IL-8 in the medium were determined. Nitrite level in the medium and DNA binding activities of NF-kappaB, AP-1, and C/EBP were assessed. NO donors induced the increase in the levels of IL-8 and nitrite in the medium as well as mRNA expression of IL-8 in AGS cells time-dependently. The induction of IL-8 by NO donors was accompanied with the activation of NF-kappaB and AP-1 but not C/EBP in AGS cells.

CONCLUSION

Large amount of NO, which may be produced by iNOS, may induce the activation of NF-kappaB and AP-1 and the expression of IL-8 in gastric epithelial cells.

Histone deacetylase inhibitors: a novel class of therapeutic agents in diabetic nephropathy

Histone deacetylase (HDAC) inhibitors are currently being tested as anticancer agents in clinical trials. Chromatin remodeling, such as through histone acetylation, is a fundamental phenomenon in eukaryotic cell biology, bearing implications to numerous physiological and pathological phenomena. Here, we discuss recent data from our own laboratory and those of others demonstrating antifibrotic and renoprotective effect of HDAC inhibitors in diabetic kidneys, and the possible mechanisms including the role of reactive oxygen species. HDAC inhibitors may prove to be a novel class of multitarget agents in the treatment of diabetic nephropathy.

Radical approach to diabetic nephropathy

There is increasing evidence that reactive oxygen species (ROS) play a major role in the development of diabetic complications. Oxidative stress is increased in diabetes and in chronic kidney disease (CKD). High glucose upregulates transforming growth factor-beta1 (TGF-beta1) and angiotensin II (Ang II) in renal cells and high glucose, TGF-beta1, and Ang II all generate and signal through ROS. ROS mediate high glucose-induced activation of protein kinase C and nuclear factor-kappaB in renal cells. Intensive glycemic control and inhibition of Ang II delay the onset and progression of diabetic nephropathy, in part, through antioxidant activity. Conventional and catalytic antioxidants were shown to prevent or delay the onset of diabetic nephropathy. Transketolase activators and poly (ADP-ribose) polymerase inhibitors were shown to block major biochemical pathways of hyperglycemic damage. Combination of strategies to prevent overproduction of ROS, to increase the removal of preformed ROS, and to block ROS-induced activation of biochemical pathways leading to cellular damage may prove to the effective in preventing the development and progression of CKD in diabetes.

Treatment of non-biodegradable cutting oil wastewater by ultrasonication-Fenton oxidation process

To treat cutting oil wastewater produced in metal surface treatment industry, Ultrasonication (US)-Fenton process, which is one of the advanced oxidation processes, was used. The optimum conditions to treat non-biodegradable pollutants using the US-Fenton process were that the application rates of H2O2 and FeSO4 were 10% and 3 g/L, respectively, the value of pH was 3, and the ultrasonication time was 30 min. It identified non-degradable pollutants such as ethylene diamine tetraacetic acid (EDTA) and Triethanolamine (TEA) in the cutting oil wastewater. TLC analysis of two compounds of treated water by the coagulation process was similar to that of raw water. However, TLC analysis of two compounds of US-Fenton process was different from that of raw water, meaning that US-Fenton process decomposed the EDTA and TEA. To study the possibility of application with the US-Fenton process to pilot plant, the pollutants treatment efficiency of three different methods, such as US-Fenton process, activated sludge process and coagulation process, in continuous experiments were compared. The removal rate of pollutants by the US-Fenton process according to the effluent time was higher than any other processes. The removal rates of COD, SS, T-N and T-P by US-Fenton process were 98, 93, 75 and 95%, respectively.

Sirolimus Inhibits Platelet-Derived Growth Factor–Induced Collagen Synthesis in Rat Vascular Smooth Muscle Cells

Vascular smooth muscle cell (VSMC) proliferation and extracellular matrix (ECM) accumulation play key roles in the development and the progression of vascular remodeling such as transplant arteriosclerosis and restenosis. The present study examined the effects of sirolimus (SRL) on platelet-derived growth factor (PDGF)-induced fibronectin secretion, collagen synthesis, and the related signaling pathways including reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPK) in rat VSMCs. Primary rat VSMCs were isolated from male Sprague-Dawley rats. Growth arrested, synchronized cells were treated with various concentrations of SRL before the addition of PDGF at 10 ng/mL. Proliferating cell nuclear antigen expression, fibronectin secretion, and the activation of extracellular signal-regulated protein kinase (ERK) and p38 MAPK were assessed by Western blot analysis, collagen synthesis by [(3)H]-proline incorporation, and cellular ROS by flow cytometry. PDGF (10 ng/mL) increased VSMC proliferation by 1.7-fold, fibronectin secretion by 1.5-fold, collagen synthesis by 2.1-fold, cellular ROS by 1.6-fold, and activation of ERK and p38 MAPK by 3.3- and 3.9-fold compared to controls. SRL above 1 nmol/L inhibited PDGF-induced VSMC proliferation and collagen synthesis but not PDGF-induced fibronectin secretion, cellular ROS, and activation of ERK and p38 MAPK. These data demonstrated that PDGF increased ECM synthesis as well as proliferation through cellular ROS and subsequent MAPK activation and that SRL inhibited PDGF-induced VSMC proliferation and collagen synthesis in a cellular ROS- and MAPK activation-independent way.

Effect of vermiculite addition on compost produced from Korean food wastes

To evaluate the effect of vermiculite addition on composting food wastes from Korean households, food wastes were composted in three small bins to which different additives were added. The following three bins were employed: in Case I, only recycled compost was composted; in Case II, food wastes with recycled compost; and in Case III, food wastes with recycled compost and vermiculite. In the experiment performed for 30 days, it was confirmed that the supplementary addition of vermiculite to the composting mixture did not significantly improve the weight loss rate and the decomposition rate of food wastes. Due to dilution through the use of inorganic vermiculite, the vermiculite addition reduced the organic matter concentration of the composting mixtures. Vermiculite addition did not raise the pH value. Weight losses of roughly 70% were observed based on calculating moisture loss as well as dry food waste loss and not considering additives, while dry food waste loss was 29.4% and 35.8% with and without the addition of vermiculite, respectively. For these experiments, the major portion of the weight loss was the loss of water. The results indicate a need to differentiate between weight loss percentages and decomposition percentages, and a need to indicate if either of these percentages includes or excludes the mass of additives.

Epithelioid angiosarcoma of the pleura: a case report

Angiosarcomas of the pleura are very rare tumors and it is difficult to differentiate them from other common pleural tumors such as mesothelioma and metastasic carcinoma clinically and pathologically. We report a case of a young Korean woman with angiosarcoma arising in the pleura. A 34-yr-old woman presented with dyspnea and chest tightness and pain for several months. A computed tomographic scan of the chest showed diffuse thickening of the left pleura and effusion with passive atelectasis. At thoracotomy the left pleura was thick and indurated. Histologically, the decorticated pleura revealed infiltration of sheets or cords of polygonal and epithelioid tumor cells showing rudimentary vascular differentiation. Immunohistochemically, the tumor cells were strongly positive for CD31, CD34, and vimentin, whereas weakly positive for factor VIII, and negative for cytokeratin, which are characteristic and specific findings of angiosarcoma.

Single dose radiation is more effective for the UV-induced activation and proliferation of melanocytes than fractionated dose radiation

PURPOSE

To establish whether the effect of fractionating radiation modifies the effects of ultraviolet (UV) radiation on epidermal melanocytes, we compared the clinical and histological effects of single high dose radiation against repeated intermediate to low dose radiation on epidermal melanocytes.

METHODS

Three minimal erythema UV doses (MED) were administered to three sites on the buttocks of healthy volunteers. One site was irradiated with 0.5 MED UV every day for 6 consecutive days, another site was irradiated with 1 MED UV every second day, and a third site received a single dose of radiation with 3 MED UV. The treatment was replicated on the other buttock. For the evaluation of UV-induced erythema and pigmentation, erythema and melanin indices were measured at 2 and 14 days post-irradiation. For purposes of histological evaluation, tissue specimens taken from each irradiated site at 2 and 14 days post-irradiation and were stained with monoclonal antibodies against Mel-5, HMB-45 and tyrosinase. Fontana-Masson silver staining, DOPA staining and split DOPA reactions were also performed.

RESULTS

At 14 days post-irradiation, UV radiation induced melanocyte activation, proliferation and melanogenesis in proportion to the radiation dose administered to each fraction. The most prominent responses were observed after single high doses of radiation.

CONCLUSION

When the total administered dose is identical, fractionation of radiation dose diminishes the effects of UV radiation on epidermal melanocytes. Furthermore, long, uninterrupted doses of UV radiation were found to more effective in inducing melanogenesis and melanocyte activation.

Modulation of skin collagen metabolism in aged and photoaged human skin in vivo

To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen alpha1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin.

Aging- and photoaging-dependent changes of enzymic and nonenzymic antioxidants in the epidermis and dermis of human skin in vivo

This is a comprehensive study of the changes in major antioxidant enzymes and antioxidant molecules during intrinsic aging and photoaging processes in the epidermis and dermis of human skin in vivo. We show that the activities of superoxide dismutase and glutathione peroxidase are not changed during these processes in human skin in vivo. Interestingly, the activity of catalase was significantly increased in the epidermis of photoaged (163%) and naturally aged (118%) skin (n = 9), but it was significantly lower in the dermis of photoaged (67% of the young skin level) and naturally aged (55%) skin compared with young (n = 7) skin. The activity of glutathione reductase was significantly higher (121%) in naturally aged epidermis. The concentration of alpha-tocopherol was significantly lower in the epidermis of photoaged (56% of young skin level) and aged (61%) skin, but this was not found to be the case in the dermis. Ascorbic acid levels were lower in both epidermis (69% and 61%) and dermis (63% and 70%) of photoaged and naturally aged skin, respectively. Gluta thione concentrations were also lower. Uric acid did not show any significant changes. Our results suggest that the components of the antioxidant defense system in human skin are probably regulated in a complex manner during the intrinsic aging and photoaging processes.

Modulation of catalase in human skin in vivo by acute and chronic UV radiation

In this study, we demonstrate that catalase is differently regulated either by acute, or chronic UV radiation during the photoaging process. 2MED of UV radiation decreased the activity and expression of catalase gradually in the epidermis and dermis at between 24 and 48 h after the UV exposure. These levels then returned to near normal by 72 h after exposure. The catalase mRNA was also decreased in the skin 24 h after UV irradiation to 50% of the control level, and then started to recover. In contrast, chronic UV irradiation over a lifetime (approximately 50 years) increased the catalase activity in the epidermis and dermis of the human skin in vivo. Our results suggest that catalase might be one of the important enzymes in the skin aging process, and that it plays an important role in the photoprotection of the skin from UV light.

Gene profile of replicative senescence is different from progeria or elderly donor

In vitro cellular senescence of human diploid fibroblast has been a good model for aging research, which shows similar phenotypes to in vivo aging. Gene expression profiling would provide an insight to understand the mechanism of senescence. Using cDNA microarray containing 384 known genes, we compared the expression profiles of three different types of aging models: replicative senescence, fibroblasts from progeria or from elderly donor. Although all of them showed senescence phenotypes, distinct sets of genes were altered in each group. Pairwise plots or cluster analysis of activation fold of gene expression revealed closer relationships between fibroblasts from progeria or from old individual, but not between replicative senescence fibroblasts and either models. Differential expression pattern of several genes were confirmed by RT-PCR. We suggest that the replicative senescence model might behave differently to other types of aging models due to the distinct gene expression.

Ultraviolet radiation increases tropoelastin mRNA expression in the epidermis of human skin in vivo

Photoaged skin contains elastotic materials in the upper reticular dermis. This phenomenon is commonly known as solar elastosis. Little is known about the mechanisms leading to the accumulation of elastotic materials in photoaged skin, however. In this study, it was demonstrated that ultraviolet irradiation induced tropoelastin mRNA expression in the keratinocytes of human skin in vivo and also in cultured human keratinocytes by in situ hybridization and reverse transcriptase polymerase chain reaction. It was also shown by northern blot analysis (n = 5) that there were increased tropoelastin mRNA levels in the forearm (sun-exposed) skin of elderly persons, compared with upper-inner arm (sun-protected) skin of the same individuals. As demonstrated by in situ hybridization compared to sun-protected skin (upper-inner arm) (n = 5), tropoelastin mRNA expression in photoaged skin was higher in keratinocytes as well as in fibroblasts. Therefore, our results suggest that keratinocytes are another source of tropoelastin production after acute and chronic ultraviolet irradiation in human skin in vivo.

Long-term results with St. Jude Medical and CarboMedics prosthetic heart valves

BACKGROUND AND AIM OF THE STUDY

The clinical evaluation and comparison of St. Jude Medical (SJM) and CarboMedics (CM) prosthetic heart valves implanted between 1988 and 1997 is presented.

METHODS

In total, 648 SJM valves were implanted in 641 patients, and 601 CM valves in 591 patients. There were 684 mitral valve replacements, 256 aortic valve replacements, 252 mitral and aortic (double) valve replacements, 16 triple valve replacements, and 41 other tricuspid-related valve replacements. Total follow up was 98%. The overall incidence of valve-related events was compared before and after establishment of a 'valve clinic' in 1993.

RESULTS

The overall hospital mortality was 3.4%; late mortality was 8.2%. The five- and ten-year survival for all patients was 92.1% and 86.2%, respectively. There were 31 episodes of thromboembolism in 27 patients (including valve thrombosis in three), 21 episodes of bleeding events in 20 patients, and 18 re-replacements of implanted valves. No structural valve deterioration was observed. Freedom from thromboembolism was 97.8% at five years and 96.3% at ten years; freedom from bleeding episodes was 98.1% and 97.6%, respectively. In terms of hospital and late mortality, and incidence of thromboembolism, hemorrhagic episodes and structural valve failure, no statistically significant differences were found between the SJM and CarboMedics patient groups. Freedom from thromboembolism was 96.7% at five years before initiation of an intensive follow up program, and 99.0% thereafter (p = 0.031). In contrast, freedom from bleeding episodes fell from 99.3% to 96.1% during the same time period (p = 0.0004).

CONCLUSION

Both the SJM and CM prosthetic heart valves performed well in our study, and no discernible differences in clinical performance of the two valves were detected. The intensive follow up program resulted in a reduced incidence of thromboembolism, but an increased number of bleeding complications. An optimum anticoagulation regimen to manage these two conflicting problems has yet to be elucidated.

Suppression of NF-kappaB activation and cytokine production by N-acetylcysteine in pancreatic acinar cells

Reactive oxygen species (ROS), generated by infiltrating neutrophils, are considered as an important regulator in the pathogenesis and development of pancreatitis. A hallmark of the inflammatory response is the induction of cytokine gene expression, which may be regulated by oxidant-sensitive transcription factor, nuclear factor-kappaB (NF-kappaB). Present study aims to investigate whether neutrophils primed by 4beta-phorbol 12beta-myristate 13alpha-acetate (PMA) affect the productions of H(2)O(2) and lipid peroxide (LPO), NF-kappaB activation and cytokine production in pancreatic acinar cells, and whether these alterations were inhibited by N-acetylcysteine (NAC) and superoxide dismutase (SOD). Neutrophils generated ROS by stimulation with PMA, which was inhibited by NAC and SOD. In acinar cells, PMA-primed neutrophils increased the productions of H(2)O(2), LPO, and cytokines both time and dose dependently. PMA-primed neutrophils resulted in the activation of two species of NF-kappaB dimers (a p50/p65 heterodimer and a p50 homodimer) in acinar cells. Both NAC and SOD inhibited neutrophil-induced, oxidant-mediated alterations in acinar cells. In conclusion, ROS, generated by neutrophils, activates NF-kappaB, resulting in upregulation of inflammatory cytokines in acinar cells. Antioxidants such as NAC might be useful antiinflammatory agents by inhibiting oxidant-mediated activation of NF-kappaB and decreasing cytokine production.

NF-kappaB and cytokines in pancreatic acinar cells

Reactive oxygen species (ROS), generated by infiltrating neutrophils, are considered as an important regulator in the pathogenesis and deveolpment of pancreatitis. A hallmark of the inflammatory response is the induction of cytokine gene expression, which may be regulated by oxidant-sensitive transcription factor, nuclear factor-kappaB (NF-KB). Present study aims to investigate whether neutrophils primed by 4beta-phorbol 12beta-myristate 13alpha-acetate (PMA) affect the productions of H2O2 and lipid peroxide (LPO), NF-kappaB activation and cytokine production in pancreatic acinar cells, and whether these alterations were inhibited by N-acetylcysteine (NAC) and superoxide dismutase (SOD). ROS generation in neutrophils increased by PMA, which was inhibited by NAC and SOD. The productions of H2O2, LPO and TNF-alpha were increased with the amounts of PMA-primed neutrophils added to acinar cells while the productions of H2O2, LPO and cytokines increased with time. PMA-primed neutrophils resulted in the activation of two species of NF-kappaB dimers (a p50/p65 heterodimer and a p50 homodimer). Both NAC and SOD inhibited neutrophil-induced alterations in acinar cells. In conclusion, ROS, generated by neutrophils, activates NF-kappaB, resulting in upregulation of inflammatory cytokines in acinar cells. Antioxidants such as NAC might be clinically useful antiinflammatory agents by inhibiting oxidant-mediated activation of NF-KB and decreasing cytokine production.

Inhibition of lipid peroxidation, NF-kappaB activation and IL-8 production by rebamipide in Helicobacter pylori-stimulated gastric epithelial cells

The present study aimed to investigate whether rebamipide, a novel antiulcer agent that has an oxygen radical scavenging activity, would inhibit lipid peroxidation, NF-kappaB activation, and IL-8 production by H. pylori. Human gastric epithelial cells (AGS and KATO III), treated with rebamipide or not were incubated in the absence or the presence of H. pylori. As a result, H. pylori significantly stimulated IL-8 production, which was similar to time course stimulation of lipid peroxidation. Other cytokines (IL-1alpha, IL-1beta, IL-6, TNF-alpha) were not stimulated by H. pylori. Treatment with H. pylori resulted in the activation of two species of NF-kappaB dimers (a p50/p65 heterodimer and a p50 homodimer). Rebamipide significantly inhibited lipid peroxidation as an indicative of oxidative damage, NF-kappaB complex formation, and IL-8 production by H. pylori. In conclusion, rebamipide may attenuate H. pylori-induced gastric inflammation by inhibiting lipid peroxidation and oxidant-mediated activation of NF-kappaB and thereby decreasing IL-8 production.

Peroral immunization of microencapsulated human VP8 in combination with cholera toxin induces intestinal antibody responses

To develop an orally delivered subunit vaccine for rotavirus infection, a trypsin cleavage product of VP4, recombinant VP8*, was expressed in Escherichia coli. The recombinant VP8* (rVP8*), purified by affinity chromatography, was reactive against human rotavirus positive serum in Western-blot analysis. To further evaluate the immunogenicity of the oral-delivered rVP8*, it was encapsulated with alginate-microsphere and administered in combination with cholera toxin (CT) as a mucosal adjuvant perorally into mice. The ELISPOT assay showed that the number of rVP8*-specific IgG1 antibody secreting cells increased about 3-fold and about 2-fold in spleen and Peyer's patch, respectively as compared to non-immune mice. In addition, the number of rVP8*-specific IgA antibody secreting cells increased about 2-fold in Peyer's patch. Finally, rVP8*-specific IgA antibody response was significantly enhanced in the intestinal fluids from the mice immunized perorally with encapsulated rVP8* and CT. Taken together, these results indicate that rVP8* possessed proper immunogenicity and it would be potentially useful as a subunit vaccine against rotavirus-associated disease through peroral immunization.

Effects of mannitol and dimethylthiourea on helicobacter pylori-induced IL-8 production in gastric epithelial cells

The present study aims at investigating the effects of mannitol and dimethylthiourea, known hydroxyl radical scavengers, on lipid peroxidation as an indicative of oxidative damage, NF-kappa B activation and IL-8 production by Helicobacter pylori in gastric epithelial cells. A human gastric epithelial cell line, AGS, treated with or without mannitol and dimethylthiourea, was incubated in the absence or the presence of H. pylori. As a result, H. pylori significantly stimulated the productions of lipid peroxide and IL-8. Treatment with H. pylori resulted in the activation of two species of NF-kappa B dimers (a p50/p65 heterodimer and a p50 homodimer). Mannitol and dimethylthiourea significantly inhibited lipid peroxide production, NF-kappa B complex formation and IL-8 production by H. pylori. In conclusion, mannitol and dimethylthiourea may attenuate H. pylori-induced gastric inflammation by inhibiting lipid peroxidation and NF-kappa B activation and thereby decreasing IL-8 production.

Rapid induction of p21WAF1 but delayed down-regulation of Cdc25A in the TGF-beta-induced cell cycle arrest of gastric carcinoma cells

Transforming growth factor-beta (TGF-beta) is a multifunctional polypeptide that inhibits cellular proliferation in most epithelial cells. cdk4 and several cyclin-dependent kinase (cdk) inhibitors (p15INK4B, p21WAF1/Cip1 and p27Kip1) have been implicated in the TGF-beta-induced cell cycle arrest. More recently, down-regulation of Cdc25A, a cdk activator, was additionally suggested as a mechanism underlying growth inhibition by TGF-beta. The existence of diverse cellular mediators of TGF-beta, however, raises the question of whether their involvement might occur in a redundant manner or coordinately in a certain cell type. Using two TGF-beta-sensitive gastric carcinoma cell lines (SNU-16 and -620), we addressed the contributory roles of several cdk inhibitors, and of cdk4 and Cdc25A, in TGF-beta-induced cell cycle arrest by comparing their temporal expression pattern in response to TGF-beta. Among the cdk inhibitors examined, p21 mRNA was most rapidly (in less than 1 h) and prominently induced by TGF-beta. In contrast, p15 mRNA was more slowly induced than p21 in SNU-620 cells, and not expressed in SNU-16 cells harbouring homozygous deletion of p15. Western blotting results confirmed the rapid increase of p21, while opposite patterns of p27 expression were observed in the two cell lines. The down-regulation of Cdc25A mRNA occurred, but was more delayed than that of p15 or p21. Until G1 arrest was established, changes in the protein levels of both Cdc25A and cdk4 were marginal. Co-immunoprecipitation with anti-cdk4 antibody showed that induced p21 associates with cdk4 and that its kinase activity is reduced by TGF-beta, which kinetically correlates closely with G1 arrest following TGF-beta treatment of both cell lines. These results suggest that in certain human epithelial cells, p21 may play an early role in TGF-beta-induced cell cycle arrest, and its cooperation with other cdk inhibitors is different depending on cell type. Delayed down-regulation of Cdc25A and cdk4 may contribute to cell adaptation to the quiescent state in the two gastric carcinoma cell lines studied.

Alterations of p16INK4A and p15INK4B genes in gastric carcinomas

BACKGROUND

It has been suggested that cyclin-dependent kinase inhibitors (CDKIs), including p16 and p15, are tumor suppressor genes. Alterations of CDKIs have been found in most types of cancer. However, little is known about the status of p16 and p15 genes, including methylation of the promoter region, in gastric carcinoma.

METHODS

Thirty-six primary gastric tumors and 9 gastric carcinoma cell lines were examined for alterations of the p16 and p15 genes. Deletion of the p16 and p15 genes was assessed by Southern blot analysis, expression by Northern blot analysis, and mutation by polymerase chain reaction-single strand conformation polymorphism followed by direct sequencing. The methylation status of the 5' CpG island of the p16 gene was evaluated using methylation-sensitive restriction enzymes, and reversal of the transcriptional block of the p16 gene was determined by Northern blot analysis after treatment with 5-aza-2'-deoxycytidine.

RESULTS

Homozygous deletions of the p16 and 15 genes from 2 of 9 gastric carcinoma cell lines were found. In contrast, no deletions were detected in 36 primary gastric tumors, and one primary tumor showed rearrangements of the p16 and p15 genes. Two gastric carcinoma cell lines showed a point mutation and an insertional mutation of the p16 gene, respectively; however, no point mutations were noted for the p16 and p15 genes in any of the primary gastric tumors. Constitutive levels of p16 mRNA expression in gastric carcinoma cell lines were quite heterogeneous; four gastric carcinoma cell lines had no detectable p16 mRNA and 6 gastric carcinoma cell lines had negligible expression of p15 mRNA. Of 10 primary gastric tumors, only 1 tumor expressed p16 mRNA. Furthermore, abnormal DNA methylation patterns of the p16 gene were found in 2 gastric carcinoma cell lines through the use of methylation-sensitive restriction enzymes. These cell lines lacked expression of p16 mRNA without deletions of the p16 gene. These transcriptional blocks were reversed by treatment with 5-aza-2'-deoxycytidine.

CONCLUSIONS

Deletions or mutations of the p16 and p15 genes are uncommon in primary gastric carcinomas. However, defective mRNA transcription, sometimes by aberrant DNA methylation, might be one of the pathways of inactivation of the p16 gene that leads to the development of gastric carcinoma.

Alterations of p16INK4A and p15INK4B genes in gastric carcinomas

BACKGROUND

It has been suggested that cyclin-dependent kinase inhibitors (CDKIs), including p16 and p15, are tumor suppressor genes. Alterations of CDKIs have been found in most types of cancer. However, little is known about the status of p16 and p15 genes, including methylation of the promoter region, in gastric carcinoma.

METHODS

Thirty-six primary gastric tumors and 9 gastric carcinoma cell lines were examined for alterations of the p16 and p15 genes. Deletion of the p16 and p15 genes was assessed by Southern blot analysis, expression by Northern blot analysis, and mutation by polymerase chain reaction-single strand conformation polymorphism followed by direct sequencing. The methylation status of the 5' CpG island of the p16 gene was evaluated using methylation-sensitive restriction enzymes, and reversal of the transcriptional block of the p16 gene was determined by Northern blot analysis after treatment with 5-aza-2'-deoxycytidine.

RESULTS

Homozygous deletions of the p16 and 15 genes from 2 of 9 gastric carcinoma cell lines were found. In contrast, no deletions were detected in 36 primary gastric tumors, and one primary tumor showed rearrangements of the p16 and p15 genes. Two gastric carcinoma cell lines showed a point mutation and an insertional mutation of the p16 gene, respectively; however, no point mutations were noted for the p16 and p15 genes in any of the primary gastric tumors. Constitutive levels of p16 mRNA expression in gastric carcinoma cell lines were quite heterogeneous; four gastric carcinoma cell lines had no detectable p16 mRNA and 6 gastric carcinoma cell lines had negligible expression of p15 mRNA. Of 10 primary gastric tumors, only 1 tumor expressed p16 mRNA. Furthermore, abnormal DNA methylation patterns of the p16 gene were found in 2 gastric carcinoma cell lines through the use of methylation-sensitive restriction enzymes. These cell lines lacked expression of p16 mRNA without deletions of the p16 gene. These transcriptional blocks were reversed by treatment with 5-aza-2'-deoxycytidine.

CONCLUSIONS

Deletions or mutations of the p16 and p15 genes are uncommon in primary gastric carcinomas. However, defective mRNA transcription, sometimes by aberrant DNA methylation, might be one of the pathways of inactivation of the p16 gene that leads to the development of gastric carcinoma.

Alterations of p16INK4A and p15INK4B genes in gastric carcinomas

BACKGROUND

It has been suggested that cyclin-dependent kinase inhibitors (CDKIs), including p16 and p15, are tumor suppressor genes. Alterations of CDKIs have been found in most types of cancer. However, little is known about the status of p16 and p15 genes, including methylation of the promoter region, in gastric carcinoma.

METHODS

Thirty-six primary gastric tumors and 9 gastric carcinoma cell lines were examined for alterations of the p16 and p15 genes. Deletion of the p16 and p15 genes was assessed by Southern blot analysis, expression by Northern blot analysis, and mutation by polymerase chain reaction-single strand conformation polymorphism followed by direct sequencing. The methylation status of the 5' CpG island of the p16 gene was evaluated using methylation-sensitive restriction enzymes, and reversal of the transcriptional block of the p16 gene was determined by Northern blot analysis after treatment with 5-aza-2'-deoxycytidine.

RESULTS

Homozygous deletions of the p16 and 15 genes from 2 of 9 gastric carcinoma cell lines were found. In contrast, no deletions were detected in 36 primary gastric tumors, and one primary tumor showed rearrangements of the p16 and p15 genes. Two gastric carcinoma cell lines showed a point mutation and an insertional mutation of the p16 gene, respectively; however, no point mutations were noted for the p16 and p15 genes in any of the primary gastric tumors. Constitutive levels of p16 mRNA expression in gastric carcinoma cell lines were quite heterogeneous; four gastric carcinoma cell lines had no detectable p16 mRNA and 6 gastric carcinoma cell lines had negligible expression of p15 mRNA. Of 10 primary gastric tumors, only 1 tumor expressed p16 mRNA. Furthermore, abnormal DNA methylation patterns of the p16 gene were found in 2 gastric carcinoma cell lines through the use of methylation-sensitive restriction enzymes. These cell lines lacked expression of p16 mRNA without deletions of the p16 gene. These transcriptional blocks were reversed by treatment with 5-aza-2'-deoxycytidine.

CONCLUSIONS

Deletions or mutations of the p16 and p15 genes are uncommon in primary gastric carcinomas. However, defective mRNA transcription, sometimes by aberrant DNA methylation, might be one of the pathways of inactivation of the p16 gene that leads to the development of gastric carcinoma.

Pathological changes according to the severity of asthma

BACKGROUND

There have been many studies concerning pathological changes in bronchial mucosa from asthmatics; however, few studies has been carried out to evaluate pathological changes according to the severity of asthma.

OBJECTIVE

This study was designed to evaluate the cellular components in bronchoalveolar lavage fluid (BALF) and histological abnormalities in asthmatics according to the severity of asthma.

METHODS

Bronchoalveolar lavages, bronchoscopic biopsies and ultrastructural examinations were performed in 13 asthmatics and 11 (BAL) or four (biopsies) non-asthmatic controls. The proportions of epithelial cells and correlations with PC20Meth which reflects bronchial hyperresponsiveness. Light microscopic examination revealed loss of epithelium, inflammatory cell infiltrations and thickening of the basement membrane which also showed significant correlation with PC20Meth. Hypertrophy of airway smooth muscles and hyperplasia of mucous glands were prominent in asthmatics but there was no difference according to the severity of asthma. Ultrastructural examination revealed that basement membrane thickening on light microscopic examination is due to the increased subepithelial collagen deposition with normal thickness of basal lamina.

CONCLUSION

These data suggest that loss of epithelial cells, infiltration of inflammatory cells, especially eosinophils, and increased deposition of subepithelial collagen play major roles in determining the severity of asthma and non-specific bronchial hyperresponsiveness.