Apoptosis of medial smooth muscle cells in the development of saccular cerebral aneurysms in rats

BACKGROUND AND PURPOSE

Using an animal model, we examined the role of apoptosis in the disappearance of medial smooth muscle cells (SMCs) during the development and growth of cerebral aneurysms.

METHODS

Various degrees of cerebral aneurysms were induced in the right anterior cerebral artery-olfactory artery bifurcations in 65 Sprague-Dawley rats with ligation of the left common carotid artery and renal hypertension. We performed in situ end labeling of fragmented DNA with the lesions in 45 rats and electron microscopic study in the other 20 rats.

RESULTS

With in situ end labeling of fragmented DNA, 4+/-3 apoptotic medial SMCs were detected in 35 of the 45 bifurcations. Apoptotic SMCs appeared in the medial layer in the "preaneurysm" group, the site speculated to show an aneurysmal change in the near future (6+/-3), and in the media in the "early aneurysm" group, which showed characteristics such as a small depression (5+/-3). In the "progressive aneurysm" group, they appeared more frequently at the aneurysmal neck (3+/-2) than the dome (1+/-1). By electron microscopic study, shrunken medial SMCs exhibiting morphological apoptotic changes such as chromatin condensation and fragmentation of the cytoplasm and nucleus were observed in the preaneurysm and early aneurysm groups and at the neck portion in the progressive aneurysm group. In the aneurysmal dome, SMCs showed late characteristics of apoptosis such as more advanced nuclear and cytoplasmic condensation and formation of apoptotic bodies.

CONCLUSIONS

The present findings indicate that there is an association between apoptosis of medial SMCs and the formation of saccular cerebral aneurysms.

Immortalization of immunologically committed Epstein-Barr virus-transformed human B-lymphoblastoid cell lines accompanied by a strong telomerase activity

The immunological characteristics and immortalization processes of three EBV-transformed human B-lymphoblastoid cell lines, N0003, N0005 and N6803, with strong telomerase and infinitively proliferating activities are described. The three cell lines were apparently immortalized: they developed a strong telomerase activity at the population doubling levels (PDLs) between 11 and 135, and continued proliferation over 250 PDLs. All the cell lines expressed CD22, CD19 and CD20 antigens. They were uniformly stained with IgM (N0005), IgG (N6803) or IgA (N0003) at early PDLs between 17 and 20, and they secreted the corresponding class of Ig into the medium; the N6803 and N0003 cell lines continued to secrete each class of Ig at decreased levels while the N0005 cell line expressed or secreted virtually no Ig after immortalization. Karyotype analysis of the immortalized cell lines showed that they were derived from a single cell because they shared a set of abnormal chromosomes within each cell population, and two of the cell lines attained clonal characteristics before they developed a strong telomerase activity. These results indicate that the three immortalized cell lines with a strong telomerase activity correspond to the intermediate stages of B-cell differentiation naturally committed to a specific Ig class, and suggest that they were derived from a B-lymphoblastoid cell committed to a specific class of Ig with poor telomerase activity, rather than from a strongly telomerase-positive B-lymphoblastoid cell either committed or multipotential.

Expressions of PDGF receptor alpha, c-Kit and Flk1 genes clustering in mouse chromosome 5 define distinct subsets of nascent mesodermal cells

In gastrulating embryos, various types of cells are generated before differentiation into specific lineages. The mesoderm of the gastrulating mouse embryo represents a group of such intermediate cells. PDGF receptor alpha (PDGFRalpha), c-Kit and fetal liver kinase 1 (Flk1) are expressed in distinctive mesodermal derivatives of post-gastrulation embryos. Their expressions during gastrulation were examined by whole mount immunostaining with monoclonal antibodies against these three receptors. The antibodies stained different mesodermal subsets in gastrulating embryos. Flow cytometry of head fold stage embryos revealed that Flk1+ mesodermal cells could be further classified by the level of c-Kit expression. To examine the possibility that hematopoietic cell differentiation is initiated from the Flk1+ mesoderm, embryonic stem (ES) cells were cultured on the OP9 or PA6 stromal cell layer; the former but not the latter supported in vitro hematopoiesis from ES cells. Flk1+ cells were detected only on the OP9 cell layer from day 3 of differentiation before the appearance of hematopoietic cells. Thus, Flk1+ cells will be required for in vitro ES cell differentiation into hematopoietic cells. The results suggest that these three receptor tyrosine kinases will be useful for defining and sorting subsets of mesodermal cells from embryos or in vitro cultured ES cells.

Evidence for participation of gliostatin/platelet-derived endothelial cell growth factor in gastric ulcer healing

Gliostatin (GLS)/Platelet-derived endothelial cell growth factor (PD-ECGF) is a protein factor that has angiogenic and thymidine phosphorylase activity. It has been recently demonstrated to be related to disease activity in rheumatoid arthritis. However, its physiological role in the gastric mucosa is unknown. In the present study, concentrations of this protein in human gastric mucosa and plasma were evaluated. Further, the effect of purified human GLS/PD-ECGF on experimental ulcer healing was investigated in the rat. The human plasma concentration of GLS/PD-ECGF was significantly higher in patients with intractable gastric ulcer than in patients with significant resolution. The tissue content was significantly higher at the gastric ulcer edge than in either the fundic or pyloric region. GLS/PD-ECGF infusion delayed ulcer healing in a dose-dependent manner. These results suggest that gastric tissue and/or circulating GLS/PD-ECGF may participate in pathology and etiology of gastric ulcers and that this mechanism may relate to the pathogenesis of RA.

[A case of idiopathic hypereosinophilic syndrome with special reference to mental disorders and brain images]

We reported a case of idiopathic hypereosinophilic syndrome with psychiatric symptoms and abnormal areas in subcortical white matter on brain MRI. The 25-year-old man was referred to us because of fever, confusional state and emotional incontinence. He soon became apathetic and emotionless. While he was confused, we studied brain CT twice and brain MRI four times. In deep white matter around the lateral ventricles and the cortices of parietal lobe, occipital lobe and cerebellar hemispheres, T1-weighted MRI revealed low intensity areas and T2-weighted MRI showed high intensity areas. After gadolinium infusion, some above-stated areas were enhanced. The lesions in the deep white matter disappeared when symptoms diminished, while lesions in the occipital cortex remained unchanged. Brain MRI studies were beneficial and useful to analyse the rare idiopathic hypereosinophilic syndrome with psychic disorders.

Expression of c-Met correlates with grade of malignancy in human astrocytic tumours: an immunohistochemical study

AIMS

Recent studies suggest the involvement of hepatocyte growth factor/scatter factor (HGF/SF) in glioma cell invasion and tumour progression. We investigated the distribution and rate of tumour cells that express c-Met protein, which is the cell-surface receptor for HGF/SF, in astrocytic tumours. The type of cells that express c-Met in tumour tissues was also identified.

METHODS AND RESULTS

c-Met expression was screened immunohistochemically in a total of 43 astrocytic tumours, including 14 low-grade astrocytomas (A), 13 anaplastic astrocytomas (AA) and 16 glioblastoma multiforme (GBM), c-Met reactivity was demonstrated predominantly in the cytoplasm of tumour cells. Bizarre large tumour cells tended to stain intensely. Higher c-Met expression levels (> or = 2+, more than 25% cells were positive) were noted in 21.4% of (A) vs. 53.8% in (AA) and 87.5% in (GBM) (P < 0.001), indicating a clear relationship between c-Met protein staining and higher grade astrocytic tumours. Moreover, c-Met immunoreactivity was also shown in tumour microvasculature, reactive astrocytes, and neurones in the cortex infiltrated by glioma cells. In 85.7% of cases containing infiltrated cortex, neurones were positive vs. no neurones in non-neoplastic regions (P < 0.002).

CONCLUSIONS

This evidence suggests that c-Met expression in the brain could be associated with astrocytoma progression and also reactive process. Immunohistochemical determination of c-Met-expressing cell types helps to understand possible roles of c-Met in tumour tissues.

Osteoclasts are present in gp130-deficient mice

Interleukin (IL)-6, IL-11, leukemia inhibitory factor, and oncostatin M similarly induce osteoclast formation in cocultures of osteoblastic cells and bone marrow cells. These cytokines share a common signal transducer, gp130, which forms a receptor complex with the specific receptor for each cytokine. To investigate the role of gp130 in osteoclast development, we examined bone tissues in gp130-deficient and wild-type newborn mice of the ICR background. Soft x-ray radiographs and microfocus x-ray computed tomographs revealed that bone marrow cavities were present in tibiae and radii of both wild-type and gp130-deficient mice. Microfocus x-ray computed tomography and histological examination demonstrated a decrease in the amount of trabeculae at the metaphysial region in tibiae and radii of the gp130-deficient mice compared with the wild-type mice. The number ofosteoclasts in gp130-deficient mice was about double that in the wild-type mice. There were no apparent differences in the distributions of alkaline phosphatase-positive osteoblasts and the osteoid surface on the trabecular bone at the metaphysial region between the wild-type and gp130-deficient mice. The volume of mineralized trabecular bones was also decreased at mandibulae, accompanied by the increased number of osteoclasts in gp130-deficient mice compared with the wild-type and heterozygous mice. These results suggest that the formation of osteoclasts is not solely dependent on gp130 signaling, at least during fetal development. The osteoclastic bone resorption in gp130-deficient mice may be caused by the functional redundancy of bone-resorbing hormones and cytokines other than those of the IL-6 family.

Expression of intestinal trefoil factor mRNA is downregulated during progression of colorectal carcinomas

AIMS

Intestinal trefoil factor is a mucosa associated trefoil peptide expressed predominantly in the goblet cells of the small and large intestine. The aim of this work was to investigate the expression of the intestinal trefoil factor gene in human colorectal cancers.

METHODS

The expression of intestinal trefoil factor mRNA was examined by northern blot analysis in 27 cases of surgically resected primary colorectal carcinoma of various stages.

RESULTS

Although intestinal trefoil factor mRNA was expressed consistently in the tumours, the levels of expression varied considerably among the cases examined. The levels of expression were low in advanced stage tumours (Dukes's B, C, and D) compared with early stage tumours (Dukes's A) (p < 0.05). In addition, there was a tendency towards a positive correlation, albeit not well defined, between the amounts of intestinal trefoil factor mRNA and the histological differentiation of tumours.

CONCLUSIONS

Intestinal trefoil factor mRNA was expressed consistently in the cases of colorectal carcinoma studied and expression was inversely associated with tumour progression.

Abnormal telomere dynamics of B-lymphoblastoid cell strains from Werner's syndrome patients transformed by Epstein-Barr virus

The characteristics of B-lymphoblastoid cell strains transformed by Epstein-Barr virus (EBV) from normal individuals and Werner's syndrome (WRN) patients were compared. We continuously passaged cell strains from 28 WRN patients and 20 normal individuals for about 2 years corresponding to over 160 population doubling levels (PDLs). First, the WRN mutation significantly suppressed the immortalization: all the 28 cell strains from WRN patients, as well as 15 out of 20 cell strains from normal individuals, died out before 160 PDLs mostly without developing a significant telomerase activity. The remaining five cell strains from normal individuals became moderately/strongly telomerase-positive and, three of them were apparently immortalized with an infinitively proliferating activity. Second, the monitoring of the telomere length of both normal and WRN cell strains during the culture period suggests that the WRN gene mutation causes abnormal dynamics of the telomere: (1) a significant proportion of WRN cell strains showed drastic shortening or lengthening of telomere lengths during cell passages compared with normal cell strains, and (2) WRN cell strains terminated their life-span at a wide range of telomere length (between 3.5 and 18.5 Kbp), whereas normal cell strains terminated within a narrow telomere length range (between 5.5 and 9 Kbp). The chromosomal aberration characteristic of WRN cells, including translocation was confirmed in our experiment. We discussed the correlation between the chromosomal instability, abnormal telomere dynamics and inability of immortalization of the WRN B-lymphobloastoid cell strains.

Molecular cloning of a new type of cDNA for pheromone biosynthesis activating neuropeptide in the silkworm, Bombyx mori

A neuropeptide named pheromone biosynthesis activating neuropeptide (PBAN) stimulates the pheromone production of lepidopteran insects. We have identified a different type of cDNA for PBAN, which shows two amino acid replacements in the region of the PBAN sequence previously reported. Single strand conformation polymorphism (SSCP) analysis revealed that the two types of cDNA originated from two allelic variants of the gene for PBAN.

Bombyxin, an insulin-related peptide of insects, reduces the major storage carbohydrates in the silkworm Bombyx mori

The effects of an insect insulin-related peptide, bombyxin, on carbohydrate metabolism were investigated in the silkworm Bombyx mori. Bombyxin lowered the concentration of the major hemolymph sugar, trehalose, in a dose-dependent manner when injected into neck-ligated larvae. Bombyxin also caused elevated trehalase activity in the midgut and muscle, suggesting that bombyxin induces hypotrehalosemia by promoting the hydrolysis of hemolymph trehalose to glucose and thereby facilitating its transport into tissues. In addition, bombyxin reduced the glycogen content in the fat body and concurrently raised the percentage of active glycogen phosphorylase in this tissue. Because hemolymph trehalose is also a major storage form of carbohydrate in insects, our results indicate that bombyxin reduces the amount of both principal storage carbohydrates in B. mori larvae. It is therefore suggested that although bombyxin is involved in the control of carbohydrate metabolism like insulin, the physiological role of bombyxin in insects is different from that of insulin in mammals.

Analysis of tissue factor and tissue factor pathway inhibitor expression in human colorectal carcinoma cell lines and metastatic sublines to the liver

To investigate the expression of tissue factor (TF) and tissue factor pathway inhibitor (TFPI) in human colorectal carcinomas, Northern blot analysis was performed in a series of human colorectal carcinoma cell lines and in normal or tumoral colorectal tissues. Of 16 human colorectal carcinoma cell lines examined, most expressed TF mRNA, though the levels of expression varied significantly. Considerably higher expression was observed in the cell line CaR-1, while lines established from metastatic lesions tended to express abundant TF mRNA. By contrast, TFPI mRNA levels were low in these high TF-expressing cell lines. TFPI was expressed abundantly in WiDr and in a few other cell lines which expressed a very low level of TF mRNA. Immunocytochemically, both proteins were stained predominantly on the cell surface; however, diffuse cytoplasmic staining for TF also was observed in CaR-1 cells. In addition, the cell surface TF activity was significantly higher in CaR-1 cells than in WiDr cells, confirming the results of mRNA analysis. The level of TF mRNA in colorectal carcinoma tissue in vivo and its ratio to the normal counterpart also varied significantly among the cases. To search for a possible role of TF/TFPI in metastasis of colorectal carcinoma cells, the expression of these genes was compared between a rectal adenocarcinoma cell line, RCM-1, and its highly metastatic subline, RCM-1 L-10. Compared with the parent line, RCM-1 L-10 expressed 7.5-fold higher levels of TF mRNA, whereas TFPI expression was not altered significantly or even decreased slightly. The higher cellular TF activity was confirmed in the metastatic subline in comparison with the parent line.

Mitogenic properties of human gastric juice

This study was performed to define the biologically active growth modulators in human gastric juice. Mitogenic activity was evaluated by the incorporation of [3H]thymidine into 3T3 fibroblasts. A negative correlation was observed between pH and mitogenic activity in gastric juice (r = -0.45, P < 0.01). The concentrations of epidermal growth factor (EGF), transforming growth factor-alpha and -beta 1 (TGF-alpha and -beta 1), platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) in gastric juice did not explain these changes in mitogenic activity. Gel filtration identified growth-stimulating activity due to small molecule mitogens (less than 13 kDa), and growth inhibitory activity only in neutral samples due to a macromolecular substance (larger than 240 kDa) susceptible to trypsin digestion and heat and acid treatments. We conclude that acidity-dependent changes in mitogenic activity observed in this study are due to appearance of acid-unstable, high-molecular-weight, growth-inhibitory substance.

Methods for the determination of mutagenic heterocyclic amines and their applications in environmental analysis

The environmental analysis of heterocyclic amines is important to preserve human health, because all these compounds are potent mutagens and many are carcinogens in experimental animals. This review summarizes the analytical methods for the determination of mutagenic heterocyclic amines and their applications to various environmental samples. High-performance liquid chromatographic methods with ultraviolet, electrochemical and fluorescence detections are commonly used for the quantification of heterocyclic amines. Moreover, liquid chromatography-mass spectrometry, gas chromatography, gas chromatography-mass spectrometry, capillary zone electrophoresis and enzyme-linked immunosorbent assay are also developed. Heterocyclic amines in complex environmental matrices are present at low parts per billion or less, so that the sample preparation influences the reliable and accurate analysis of these compounds. Mutagenic heterocyclic amines are widely distributed in a number of ambient environmental components such as airbone particles, diesel-exhaust particles, cigarette smoke, cooking fumes, rain water, sewage water, incineration-ash and soil. These facts suggest that mutagenic heterocyclic amines are likely to be ubiquitous environmental pollutants and humans are continually exposed to these compounds in normal daily life.

Expression of bone morphogenetic proteins of human neoplastic epithelial cells

Bone morphogenetic proteins (BMPs) are crucial factors of osteogenesis. We investigated the expressions of BMP subtypes in human salivary adenocarcinoma cell line (HSG-S8), tongue squamous cell (HSC-4) and gingival squamous cell (Ca9-22) carcinoma cell lines, gastric poorly differentiated adenocarcinoma cell (MNK45) and signet ring cell (KATOIII) carcinoma cell lines, rectal adenocarcinoma (RCM-1, RCM-2, and RCM-3), and thyroid (8505C) and bladder (T24) carcinoma cell lines by reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR disclosed that BMP-1 was expressed in all cell lines examined, and BMP-2 was amplified in almost all cells except MKN45. Two squamous cell carcinomas, HSC-4 and Ca9-22, and KATOIII expressed only BMP-1 and BMP-2. MKN45 did not express BMP-2, but expressed BMP-7 and weakly BMP-4 and BMP-5. In addition to the expression BMP-7, and HSG-S8 expressed BMP-6. These findings indicated that the neoplastic epithelial cells possessed a rather great potency to express BMP mRNAs. On the other hand, among these carcinoma cells, HSG-S8 solely induced bone in nude mouse tumors, and HSC-4 and KATOIII contained many calcified masses in tumors while the rest did not induce either.

Mutation and haplotype analyses of the Werner's syndrome gene based on its genomic structure: genetic epidemiology in the Japanese population

The correlation between mutations in the Werner's syndrome (WRN) gene and the haplotypes of surrounding markers was studied in Japanese patients. We have elucidated the genomic structure of WRN helicase, and found five additional mutations, designated mutations 6-10. Mutations 4 and 6 were found to be the two major mutations in this population; these mutations comprised 50.8% and 17.5%, respectively, of the total in a sample of 126 apparently unrelated chromosomes. Almost all the patients homozygous for mutation 4 shared a haplotype around the WRN gene, consistent with the view that they are derived from a single ancestor. This important advantage demonstrated in the identification of the WRN gene suggests that the Japanese present a unique population for the cloning of other disease genes. The conserved haplotype was observed across 19 loci, extending a distance estimated to be more than 1.4 Mbp around the WRN gene. This haplotype is rare among random Japanese individuals. Unexpectedly, all the nine patients homozygous for mutation 6 shared a haplotype that was identical to this haplotype at 18 of these 19 markers. These results suggest that mutations 4 and 6 arose independently in almost identical rare haplotypes. The remaining mutations (1, 5, 7, 8, 9, and 10) occurred rarely, and were each associated with different haplotypes.

Ten-year follow-up of a patient with pacemaker induced superior vena cava syndrome

A woman with persistent pacemaker induced superior vena cava syndrome was stable for 10 years. Serial follow-up venography, however, demonstrated a continuous process of major vein occlusion and the development of collateral circulation, the effectiveness of which warrants a favorable prognosis in this pacemaker related syndrome.

[Simplification of on-line connection of analyzers and standardization problems]

On-line connection of automated analyzers to laboratory information system (LIS) reduces mistakes in inputing data for each samples. It also makes reporting faster in clinical laboratory. Moreover, connection of these instruments with sample transporting system enables analyses without touching samples directly. It, however, costs extremely high to construct such a system. It is because every automated analyzer uses different connecting protocol, so that we have to make a different program for each machine. For solving this problem, we have to make a standard for connecting protocol. It is very difficult to make a standard protocol fitting on all of the analyzers, considering its cost and other things. Furthermore, it must take a few decades to spreading the standard through the end users. ICCLS and NCCLS has been taking a central role for this problem since 1996, with a five-year plan to make an international standard. Until the standard will be laid, each clinical laboratories have to pay high costs to construct their systems, connecting different manufacturers' analyzers each other. Thus, we have developed a novel system which enables us to construct a laboratory automation system in a shorter time. For realizing this new system, we have reduced the number of connecting protocols for analyzers. Moreover, we have corrected the flow of laboratory works in order. Each programs are put together into a system as parts, or modules. This software system is now in operation in the clinical laboratory of Kochi Medical School. In this report, we describe the construction of this novel software system, and the effect obtained by using this system. Furthermore, we would show problems and things to be improved for making international standards for communication protocols between host and analyzing instruments.

PDGFR alpha expression during mouse embryogenesis: immunolocalization analyzed by whole-mount immunohistostaining using the monoclonal anti-mouse PDGFR alpha antibody APA5

We investigated the cells that express platelet-derived growth factor receptor alpha (PDGFR alpha) during mouse embryogenesis. PDGFR alpha expression has been identified by in situ hybridization or immunohistochemistry using polyclonal antibodies on tissue sectins. Because no immunostaining study using whole-mount specimens has been published to date, we established a new monoclonal antibody (MAb), APA5, for this purpose. Our results differed in that APA5 stained only the paraxial mesoderm, whereas other investigators concluded that most if not all mesodermal cells expressed PDGFR alpha. Moreover, we did not find PDGFR alpha expression in embryonic erythrocytes, which have been previously suggested to express PDGFR alpha. On the basis of our present results, we wish to revise the proposed PDGFR alpha expression as follows. At the pregastrulation stage, PDGFR alpha is expressed only in primitive endoderm, particularly that in the ectoplacental cone. On gastrulation, it is expressed at high levels in the paraxial mesoderm. This expression continues after its differentiation into the somite. Along with the differentiation and migration of the sclerotome, PDGFR alpha + cells begin to become distributed throughout the embryonal mesenchyme. During organogenesis, particularly intense staining is detected in regions of epithelial and mesenchymal interaction, such as the tooth bud and bronchi. In addition to mesodermal derivatives, the developing lens, apical ectodermal ridge, glial precursor, cardiac valves, and choroid plexus express PDGFR alpha. Our results with whole-mount immunostaining show that PDGFR alpha is abundantly expressed and may play important roles during embryogenesis.