Eicosapentaenoic acid enhances myo-inositol uptake in cultured human aortic smooth muscle cells

The effects of elevated glucose and Eicosapentaenoic acid (EPA, 20:5) on myoinositol uptake in human aortic smooth muscle cells (HASMC) were evaluated. Myo-inositol incorporation into HASMC was dependent on an active transport system via Na(+)-K+ ATPase activity based on the results with Na+ deprivation and Ouabain (5 mM). Although glucose (27.5, 55 mM) inhibited 2-[3H] myo-inositol uptake, the addition of EPA (3 x 10(-4) M) prevented glucose-mediated inhibition. In addition, EPA potentiated Na(+)-K+ ATPase activity of HASMC. Since EPA decrease glucose-mediated inhibition of myo-inositol uptake, this agent might ameliorate aortic smooth muscle cell function associated with diabetes.

Increase in intracellular calcium ion in smooth muscle cells induced by low-density lipoprotein

It was investigated whether low-density lipoprotein (LDL) had effects on intracellular Ca2+ concentration in the smooth muscle cell (SMC). LDL promoted SMC proliferation and increased intracellular Ca2+ by a two-phase pattern, an initial peak and a following plateau. Each phase was suppressed by treatment with ryanodine or extracellular Ca(2+)-free buffer. This increase in intracellular Ca2+ was also suppressed by anti-LDL receptor antibody. Moreover, inositol triphosphate (IP3) was elevated with short-term LDL treatment. Since SMC proliferation is the most important event in atherosclerosis and LDL is one of the main risk factors, it was concluded that LDL might trigger SMC proliferation by increasing IP3 and intracellular Ca2+ through LDL receptor.

Molecular cloning and identification of two types of hamster cyclin-dependent kinases: cdk2 and cdk2L

We isolated two types of hamster cyclin-dependent kinase 2 (cdk2) cDNAs from BHK21 cells derived from Golden hamsters. One type of cdk2 (cdk2hm) encodes the 32 kDa protein consisting of 298 predicted amino acids and shows strong homology to the cdk2 cDNAs of humans and Xenopus. The other cdk2 (cdk2Lhm) encodes the 38 kDa protein containing the insertion of 48 amino acids in the cdk2hm protein. Immunoblotting analysis suggested that these two types of cdk2 protein exist in mammalian cells. The cdk2hm has the activity of protein kinase, while the cdk2Lhm does not, however, both bind with cyclin E.

Evaluation of serum amyloid A protein as an acute-phase reactive protein in horses

Serum amyloid A protein (SAA) was isolated from equine acute-phase serum by repeating Sephadex G-75 gel filtration 3 times. Quantitative measurement of equine SAA was performed by the single radial immunodiffusion technique with rabbit anti-equine SAA serum. In clinically normal horses, the SAA concentration remained relatively high from immediately after birth up to 1 week of age. After this the concentration showed periodic fluctiation in the range of approximately 13 to 30 micrograms/ml. The mean (+/- SD) concentration of SAA in foals (< or = 12 months old) and in adult horses (> or = 18 months old) was 19.37 +/- 9.41 and 21.53 +/- 9.81 micrograms/ml, respectively. In mares during the perinatal period, the SAA concentration remained stable and within the normal range for 4 months before parturition. After foaling, it increased quickly and reached a peak value of 136.78 +/- 56.74 micrograms/ml on day 3 postpartum, and then began to decrease at 2 weeks postpartum returning to within the normal range by 1 month postpartum. In horses with experimentally induced inflammation, the SAA concentration increased quickly, and reached the highest value, approximately 4 to 20 times higher than pre-treatment values, on day 2 after treatment. It then returned to the base line values within 10 days to 4 weeks, concurrent with the disappearance of local inflammatory signs. The SAA concentration was very high in most horses with clinical signs of inflammation. It was concluded from these data that equine SAA was a sensitive acute-phase reactive protein which increased in the early phase of various acute inflammations.

Health problems among Vietnamese refugees resettled in Japan

A medical examination of 932 Vietnamese refugees was conducted within 1 month of their resettlement in Japan between 1989 and 1991. A variety of abnormalities were detected, including parasitic disease (78% prevalence), anemia (12%), HBsAg positive state (14%), liver dysfunction (10%), hypertension (0.8%), active pulmonary tuberculosis (2%) and syphilis (0.7%). These rates were still as high as the prevalence in previous studies of earlier immigrants from Vietnam. The high frequency of infectious diseases in recent Vietnamese refugees compared with the Japanese community leads to a recommendation for continuing medical examinations and treatment for new Vietnamese refugees.

Ultrastructure of calcified muscle fibres at the implantation site of demineralized bone matrix gelatin

To clarify the mechanism of calcification during new bone formation induced by demineralized bone matrix gelatin (BMG), BMG was implanted into the skeletal muscle of Sprague-Dawley (SD) rats and histological changes were examined 1,2,3,5,7 and 10 days later. From day 2 after implantation, calcification was observed in muscle fibres near the implanted BMG. Calcification of the BMG ('acellular mineral deposition') was first seen on day 3 and in both, calcification increased. The calcification of muscle fibre was first seen in the sarcoplasmic reticulum (SR) and then in mitochondria or lipid droplet-like structures of satellite cells. The muscle mineral deposition occurred without osteogenic cells and matrix vesicles in the same way as 'acellular mineral deposition'.

Role of marginal stress fibers formed in the rat vascular endothelial cells

Fluorescence cytochemistry using en face preparations of rat vascular endothelial cells (ECs) revealed the localization of actin, fibronectin (FN) and fibronectin receptor (FNR) along not only central stress fibers (SFs) but also the cell margins. Electron microscopy showed very close proximity between the topographical distribution of intracellular microfilament bundles and that of subendothelial FN in the EC margins. Therefore, these basal and marginal actin cables may be comparable to the well-established central SFs present in ECs. Formation of the central SFs was induced in ECs or mesothelial cells in response to tension, by which their cellular integrity seems to be effectively maintained. However, even when central SF formation was inhibited by cytochalasin D, the ECs with marginal SFs showed high resistance to mechanical tension, whereas mesenteric mesothelial cells having no such fibers easily lost their integrity. Thus, together with central SFs, the marginal SFs characteristic of rat vascular ECs may play an essential role in strengthening cell-matrix adhesion.

Electrospray ionization-mass spectrometric analysis of serum transferrin isoforms in patients with carbohydrate-deficient glycoprotein syndrome

We previously reported that the carbohydrate-deficient glycoprotein (CDG) syndrome is an asparagine-N-linked sugar chain transfer deficiency [Yamashita et al. (1993) J. Biol. Chem. 268, 5783-5789]. In order to confirm this hypothesis, we applied electrospray ionization-mass spectrometric analysis to transferrin isoforms purified from patients with the CDG syndrome. Transferrin isoforms containing 4, 2, and 0 sialic acid residues, S4, S2, and S0, were separated by Mono Q anion exchange column chromatography from serum of a patient with the CDG syndrome. The molecular masses of S4, S2, and S0 were determined to be 79,570 +/- 5, 77,364 +/- 6, and 75,157 +/- 6 Da by electrospray ionization mass spectrometry (ESI/MS). The differences between S4 and S2, and between S2 and S0 were both in accordance with the molecular mass of a disialylated biantennary sugar chain [Neu5Ac alpha 2-->6Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6(Neu5Ac alpha 2-->6Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->3)Man beta 1-->4GlcNAc beta 1-->4GlcNAc] (2,206 Da), showing that S0 is nonglycosylated, and that S4 and S2 carry 2 and 1 mol of asparagine-N-linked sugar chains, respectively. The nonglycosylated asparagine site of S2 was elucidated to be random by high performance liquid chromatography-ESI/MS of a tryptic peptide of reduced and pyridylethylated S2.ESI/MS analysis of transferrin purified through one step from serum is applicable for a definite diagnosis of the CDG syndrome.

Immunocytochemical identification of growth hormone (GH) cells in the pituitary of three anuran species using an antiserum against purified bullfrog GH

An antiserum was prepared against the recently purified bullfrog (bf) growth hormone (GH); it was applied to sections of brain and pituitary of three urodele (Ambystoma, Pleurodeles and Cynops) and three anuran (Xenopus, Bufo vulgaris and B. japonicus) species. No immunostaining was obtained in the urodele pituitary, being consistent with the results of immunoblot analysis of the pituitary homogenate. In the three anuran species, strong immunoreactivity was observed in GH cells that were concentrated in the posterodorsal region of the pars distalis. No GH-like immunoreactivity was detectable in the brain of any of the species. A comparison using adjacent sections stained with anti-bf prolactin (PRL) confirmed the anteroventral localization of PRL cells. Colocalization of GH and PRL was not apparent. These data suggest that the molecular structure of amphibian GHs is considerably different between anurans and urodeles. The antiserum used in the present work shows a high species specificity, recognizing only anuran GHs. In contrast anti-bfPRL labeled PRL cells in all the amphibian species studied in the present work, suggesting that PRLs possess common amino acid sequences recognized by the anti-bfPRL.

Morphological study of the cataractous lens of the senescence accelerated mouse

A murine model of accelerated aging, the senescence accelerated mouse (SAM), has been developed. There are three accelerated senescence-resistant (SAM-R) strains and eight senescence-prone (SAM-P) strains. The SAM-P strains have an earlier onset and more rapid advancement of senescence resulting from a significantly shorter lifespan compared with the SAM-R strains. Spontaneous cataracts have been found in some individuals of the SAM-P/9 strain. The SAM-P/1 strain, which was used in the present study, has such systemic senescent characteristics as senile amyloidosis and alopecia, but it was previously thought that cataract does not occur in this strain. However, we found cataractous changes in the lens of these animals at early stages of their life. The earliest change was the appearance of a ripple-mark body at about 3 months of age. The number of rippled rings increased with age. These changes later induced refractive distortion of retinal vessels. Whole-mount flat preparations of the epithelium showed that the number of cells was markedly decreased at the advanced stages of cataract. At the late stages of life the lens cortex became liquefied and developed into a mature cataract. Cataract formation in this strain may be related to reduced viability of the lens epithelium.

Significance of serum markers pepsinogen I and II for chronic atrophic gastritis, peptic ulcer, and gastric cancer

Chronic atrophic gastritis (CAG) is closely correlated with gastric cancer and is predominant in Japan. Epidemiologically, food habits are the primary factor in both CAG and gastric cancer. Two potential serum markers for CAG have recently been investigated, i.e., the concentration of serum pepsinogen (PG) and the presence of serum antibodies against Helicobacter pylori. Serum PG I and II and the PG I:PG II ratio have been reported to be useful as indicators of recurrent peptic ulcer and for screening of patients at risk from gastric cancer. In this study, we examined PG I and II in serum from 483 patients by RIA (DAINABOT), and endoscopic examination performed in the same patients before serological assay revealed CAG in 68, peptic ulcer in 91, and gastric cancer in 48. Analysis of the mean values according to patients age showed that CAG patients in their forties to eighties had low (< 40 ng/ml) levels of PG I, peptic ulcer patients in their teens to eighties had high (> or = 70 ng/ml) levels, except for those in their seventies, and gastric cancer patients in their twenties to sixties had low (< 3.0) PG I:PG II ratios, except for those in their sixties. Thus serum PG assay has potential utility for detection of CAG, peptic ulcer, and gastric cancer.

Stimulatory effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on insulin and glucagon release from the isolated perfused rat pancreas

Rat pancreas perfusion was performed to study the effects of pituitary adenylate cyclase activating polypeptide (PACAP) on pancreatic hormone release. Under the perfusate glucose concentration of 5.5 mmol/l, 0.1 nmol/l PACAP27 significantly stimulated both insulin and glucagon release. The degree of stimulation was in a dose dependent manner. The stimulation of insulin release was clearly dependent on the perfusate glucose concentration, when compared with 2.8, 5.5 and 8.3 mmol/l. The potency of PACAP38 on the stimulation of insulin release was greater than that of PACAP27 at 5.5 mmol/l of perfusate glucose concentration, but not at 8.3 mmol/l. No differences for glucagon and cAMP release were found between the two peptides. PACAP's stimulatory effects on insulin and glucagon release were completely abolished by an equimolar and ten times lower concentration of somatostatin, respectively. The physiologic significance of these potent effects of PACAP's islet hormones release must be clarified by further studies.

Induction of inflammatory cytokines in the pleural effusion of cancer patients after the administration of an immunomodulator, OK-432: role of IL-8 for neutrophil infiltration

When OK-432, a well-known streptococcal preparation for an anti-tumour drug, was administered into the pleural cavity of patients with malignant pleurisy, a rapid and prominent leukocytosis, predominantly consisting of neutrophils, was observed in the cavity. Neutrophil infiltration usually peaked 6-9 h after OK-432 administration, and levelled down after 24 h. Prior to the neutrophil accumulation, transient but marked elevation of various inflammatory cytokine levels including IL-1 beta, TNF-alpha, IL-8 and G-CSF was observed. In particular, IL-8 levels increased more than 10-fold, while GM-CSF did not change significantly. A good correlation between IL-8 levels and neutrophil chemotactic response was observed particularly during 0-3 h. Specific neutralization or removal of IL-8 by antibody column abrogated half of the neutrophil chemotaxis, while neutralization of C5a removed around 40%. Sequential removal of IL-8 and C5a abrogated totally 80% of chemotaxis, confirming that these two factors are mostly responsible for the neutrophil chemotaxis in the pleural fluids. These results have suggested that rapid neutrophil infiltration induced by OK-432 in vivo is ascribable largely to IL-8 and in part to C5a.

[MRSA--detection of mecA and its regulatory genes]

Methicillin resistance in S.aureus and S.epidermidis strains is primarily due to production of a new penicillin-binding protein PBP2' with extremely low binding affinity to most beta-lactam antibiotics. The structural gene for PBP2', mecA, is detectable in clinical specimens by using the polymerase chain reaction (PCR). Amplified target DNA of 630bp can be resolved on ethidium bromide-stained gels, and hybridized with a probe conjugated to alkaline phosphatase. Survey for the mecA gene in 304 staphylococci revealed a good correlation between the presence of mecA and cultivation on agar plates with 4 micrograms/ml of oxacillin, although 3% of sensitive S. aureus strains had the mecA gene. On the other hand, analysis of the regulatory genes (orf 1 and 2) of methicillin resistance was performed on methicillin-resistant S.aureus strains N315 and MR108, demonstrating that the genome of MR108 lacks orf 2 which encodes the repressor protein (Hiramatsu et al., see Ref.5). The regulatory genes of mecA were surveyed for 192 staphylococci by using PCR and allele-specific oligonucleotide probes: 76% of resistant S. aureus strains and 48% of resistant S. epidermidis strains possessed orf 1 corresponding to MR108 (constitutive-type strain), while the remainder of the resistant strains and two strains of sensitive S. epidermidis had two orfs of N315 (inducible-type strain). Furthermore, it appeared that mutation of the femA gene might not be an additional factor for expression of methicillin resistance. These observations suggest that mecA and its regulatory genes should be examined to understand how the genetic background contributed to the phenotypic expression of methicillin resistance in clinical strains.

[Detection of methicillin-resistant Staphylococcus aureus using PCR and non-radioactive DNA probes (II)]

Methicillin resistance in staphylococci is primarily due to the presence of a mec A gene which encodes the novel penicillin-binding protein 2'. Some chromosomal factors, fem A and fem B, also participate in the expression of methicillin resistance in S. aureus. This study was designed to detect mec A, fem A and fem B genes for identification of staphylococcal species and for discrimination of methicillin-resistant cells. Three different pairs of DNA primers (PBP2'AF-PBP2'AR, fem AF-fem AR and fem BF-fem BR) complementary to unique regions of mec A, fem A and fem B genes were synthesized for use in polymerase chain reaction with DNAs of methicillin-sensitive S. aureus (MSSA), S. epidermidis, methicillin-resistant S. aureus (MRSA) and S. epidermidis. Amplified target DNAs of 630, 509, and 651 bp were resolved on ethidium bromide-stained gel, and hybridized to DNA probes conjugated to alkaline phosphatase. When applied to pure cultures on the MRSA screen agar, all three DNA probes tested detected MRSA in 47 of 61 culture-positive specimens (77.1%); the detection ratio of MRSA with mec A and either fem A or fem B probes was increased to 95.9%. By contrast, the fem A and fem B probes did not detect S. epidermidis. The result of detecting these species streaked on mannitol-salt agar were similar, while the detection of MSSA with the fem A and fem B probes was incomplete irrespective of the presence or absence of mec A. These findings suggest a good correlation between cultivation and DNA probe assay with respect to MRSA detection.

A possible role for Epstein-Barr virus in tumorigenesis after immunosuppression in cases of renal transplantation

Eight secondary malignancies developing after renal transplantation were investigated in terms of a possible role of the Epstein-Barr virus (EBV). In five cases, four gastric cancers and one colonic cancer, the presence of EBV was proven by the polymerase chain reaction (PCR), all four gastric lesions being confirmed to have a massive EBV infection by in situ hybridization. Two cases demonstrated monoclonal infection with EBV, as indicated by a single band of the lymphocyte-defined membrane antigen tandem-repeat gene using PCR, and were immunohistochemically positive for the latent membrane protein 1. Our series suggests that gastrointestinal cancer predominates as a secondary malignancy in states of induced severe immunosuppression, and that EBV may play an important role in tumorigenesis as an oncovirus.

[TSH receptors and signal transduction]

The TSH receptors constitute one of the main part of the signal transduction in thyroid cells and are the main biochemical targets in pathological changes. Recent molecular cloning of the TSH receptor and site-directed mutagenesis experiments have provided new evidence. It is well-established that TSH activates the cAMP cascade. Recent evidence however suggests that TSH can also activate the PIP2 cascade, but not anti-TSH receptor antibody. Specific alpha-subunits of the GTP binding protein modulate the stimulation of both pathways. Moreover, the thyroid diseases linked to the mutation of the GTP binding protein are seen. Although the TSH action in thyrocytes, through both pathways, are distinct, they are too complicated to classify clearly. The mechanism of the TSH stimulating pathway and the TSH function in thyrocytes are reviewed.

[An experimental study of catheter ablation using microwave energy via coaxial electrode catheter]

The purpose of this study was to examine the efficacy, arrhythmogenicity, and the size of ablated lesions of catheter ablation with microwave energy. Microwave energy generated by a device with a frequency of 2450 MHz, was delivered via a bipolar electrode coaxial catheter with an electrode ball tip. Microwave ablation was applied (50 watts for 15-150 sec.) on the left ventricular endocardium in 6 dogs. No ventricular arrhythmia occurred during ablation in any of the dogs when microwave catheter ablation was applied for less than 45 sec. However, when the duration of microwave catheter ablation was longer than 45-60 sec, ventricular premature contractions were observed in all 6 dogs. When ablation time was set for a longer time, the dogs developed nonsustained ventricular tachycardias. Nevertheless, ventricular arrhythmias after ablation did not occur in all dogs. Ventricular programmed stimulation after ablation did not induce ventricular tachycardia in any of the dogs. When ablation time lasted more than 120 sec, the coagulation layer was extended to the epicardium in all 6 dogs. The results of this study suggest that microwave ablation is feasible for the treatment of tachyarrhythmias from a deep focus of the ventricular myocardium.