[Evaluation of a latex agglutination method for detecting and characterizing verotoxin (VT) produced by Escherichia coli]

The detection of VT produced by Escherichia coli is very important for the identification of verotoxin-producing Escherichia coli (VTEC). The latex agglutination reagents (Denka Seiken Co. Ltd, Tokyo) which was developed to detect VT was compared with the vero cell bioassay or polymerase chain reaction method. A total 147 VT-positive strains (109 serotype O157:H 7/- and 38 non-O157 serotype) and 31 VT-negative strains which were isolated from human were investigated. In addition, a total of 79 VT-positive strains (14 serotype O157:H7/- and 65 non-O157 serotype) and 79 VT-negative strains which were isolated from animals were also examined. The latex agglutination assay for the human isolates showed the 100% sensitivity, specificity and agreement. The assay for the animal isolates showed 94.9% sensitivity, 100% specificity and 97.5% agreement. Although 4 of 8 strains isolated from swine which produce VT2 variant toxin (VT2e) failed in detecting verotoxin by latex agglutination assay, VT2e was not related to human infections. We conclude that this latex agglutination reagent is highly sensitive and specific for detecting and characterizing VT of E. coli. The method is reliable, easy to perform at any laboratories.

[Effects of topical corticosteroids on subepithelial haze after excimer laser corneal surgery--objective and quantitative method for evaluating haze]

To examine the effectiveness of topical corticosteroids in decreasing subepithelial haze induced by excimer laser keratectomy, we performed excimer laser keratectomy on 24 eyes of 12 albino rabbits using a scanning excimer laser system (EC-5000, NIDEK, Japan). Topical dexamethasone 0.1% was applied topically to 8 corneas after surgery (steroid group), but not to the others (control group). Slit-lamp biomicroscopic examination and objective measurement of scattered light from subepithelial haze were performed before and 2, 4, 8 and 12 weeks after surgery, the rabbits were killed after 2 or 12 weeks and the eyes were examined histologically. In both groups, densitometric values of scattered light intensity increased up to 4 weeks after surgery, and then decreased gradually. However, the values of the steroid group were larger than those of the control group at all stages, and the values of the steroid group at 12 weeks after surgery were similar to preoperative values. There was statistically significant difference in scattered light intensity between the two groups (p < 0.005). Two weeks after surgery, the corneas of the control group showed epithelial hyperplasia and a remarkable increase in activated keratocytes and subepithelial fibrous tissues. However, in the steroid group these light microscopic findings could not be observed. At 12 weeks after surgery, the corneas of the control group retained a small amount of activated keratocytes and fibrous tissues, and those of the steroid group were normal. This study suggests that a short course of topical corticosteroids may be very effective in decreasing subepithelial haze after excimer laser corneal surgery.

Ganglioside composition of the human cranial nerves, with special reference to pathophysiology of Miller Fisher syndrome

Total ganglioside fractions from the human cranial nerves purified on a Phenyl Sepharose column, were given mild alkaline treatment, after which their composition and amounts of lipid-bound sialic acid were determined by HPTLC-densitometry with resorcinol as the coloring reagent. The total amounts of lipid-bound sialic acid were 156.5 ng/mg of wet tissue in the Ist cranial nerve (olfactory tract) and 131.9 ng/mg in the IInd nerve, greater than the amounts in the other nerves (99.1-120.0 ng/mg). The Ist, IInd, and VIIIth nerves had GM4, but not LM1. It may reflect their histological feature of the central nervous system. The IIIrd, IVth, and VIth nerves, as well as the IInd, had significantly higher percentages of GQ1b (11.6-13.2%) than the other nerves (5.2-8.4%). The high proportion of GQ1b specific to these three cranial nerves involved in the ocular movement lends support to the role of serum anti-GQ1b antibody in the pathogenetic mechanisms of ophthalmoplegia in Miller Fisher syndrome and Guillain-Barré syndrome.

P21waf-1/cip-1/sdi-1 is expressed at G1 phase in primary culture of hepatocytes from old rats, presumably preventing the cells from entering the S phase of the cell cycle

To elucidate whether p21waf-1/cip-1/sdi-1 expression is associated with loss of growth potential of hepatocytes of old rats, we determined p21waf-1/cip-1/sdi-1 expression of hepatocytes from old (30 months) rats during the cell cycle in primary culture. A high level of expression of p21waf-1/cip-1/sdi-1 was detected at the G1 phase in old-rat hepatocytes, but after the S phase in young-rat hepatocytes. Consistently, the incidence of the cells positive for p21waf-1/cip-1/sdi-1 in nuclei before entering the S phase was significantly higher in old-rat hepatocytes than in young-rat hepatocytes. These results account for the loss of growth potential of old-rat hepatocytes in vitro and the marked retardation of regeneration of liver in old rats in vivo.

Expression of p21(waf-1/cip-1) is significantly induced in the livers of LEC rats with chronic liver injury

It is reported that hepatocytes isolated from LEC rats with chronic liver injury show reduced growth activity in primary culture. To elucidate the molecular basis of this phenomenon, we examined expression of p21(waf-1/ciP-1) and p27, cyclin-dependent kinase inhibitors, by northern blot analysis. The expression of p21(waf-1/cip-1 ) in the LEC rat liver was 3-fold higher than that of age-matched SD rat liver, while there was no significant difference in p27 expression level. Western blot analysis also revealed a significant increase in p21(waf-1/cip-1) in the nuclear matrix fraction of the LEC rat liver. Immunohistochemically, p21(waf-1/cip-1) was detected in the nuclei of normal LEC rat hepatocytes, but not in those of hepatocellular carcinoma cells, suggesting selective growth of neoplastic hepatocytes.

Phase-Dependent effects of transforming growth factor beta 1 on osteoblastic markers of human osteoblastic cell line sV-HFO during mineralization

A human osteoblastic cell line (SV-HFO) established in our laboratory expresses osteoblastic markers, including mineralization in vitro, in response to differentiation-inducing agents such as dexamethasone. In this study, we examined the effects of transforming growth factor beta 1 (TGF-beta 1) on the mineralization of SV-HFO cells and show that TGF-beta 1 inhibited the mineralization of the cells via down regulation of tetranectin and alkaline phosphatase without influencing other osteoblastic markers. To examine precisely the effects of TGF-beta 1 on the process of mineralization, we tentatively divided the whole process of mineralization into four phases: induced ALP activity (days 0-5), maximal ALP activity (days 5-10), early mineralization (days 10-15), and progressive mineralization (days 15-20). These inhibitory effects of TGF-beta 1 on the expression of tetranectin and alkaline phosphatase, like that on mineralization, were observed only when TGF-beta 1 was applied in the early phase of the process of mineralization. On the other hand, the other osteoblastic markers were not influenced by treatment with TGF-beta 1. These results suggest that TGF-beta 1 may inhibit mineralization of osteoblasts by the downregulation of tetranectin and alkaline phosphatase expression in the early phase. Thus, TGF-beta 1 has phase-dependent effects on a human osteoblastic cell line during the process of mineralization.

Abnormal accumulation of copper in LEC rat liver induces expression of p53 and nuclear matrix-bound p21(waf 1/cip 1)

The LEC rat is an inbred mutant strain which spontaneously develops liver injury and subsequent liver cancer. Liver injury in LEC rats has recently been shown to be closely related to abnormal copper accumulation in the liver. Previously, we reported that LEC rat hepatocytes lose their growth potential, probably allowing selective growth of preneoplastic cells. In this study, to elucidate the effects of copper accumulation on the growth activity of LEC rat hepatocytes, we examined the growth activity and the expression of p53 and p21(waf 1/cip 1) in the livers of LEC rats fed on either a control or a low-copper diet. Potential for cell proliferation of hepatocytes obtained from normal diet fed LEC rats was almost comparable to that of the cells from age-matched Sprague-Dawley (SD) rats. Northern blot analysis showed that the expression of p53 and p21(waf 1/cip 1) was significantly high in the livers of LEC rats fed a control diet, while the expression of p53 and p21(waf 1/cip 1) in the LEC rats fed a low-copper diet was as low as that of SD rat livers. Western blot analysis consistently showed that the amount of p21(waf 1/cip 1) bound to the nuclear matrix scaffold of the LEC rat liver was reduced by feeding a low-copper diet. These findings suggest that abnormal accumulation of copper induced the expression of p53 and p21(waf 1/cip 1), resulting in the inhibition of cell proliferation of LEC rat hepatocytes.

[NO2 inhalation in two smokers and two non-smokers]

Four healthy men were exposed to an anti-rust substance in a stainless steel tank. Acute respiratory failure developed in two of them, both non-smokers. Their chest roentgenograms revealed marked infiltration, which suggested pulmonary edema due to the inhalation of NO2 and hydrogen fluoride. These two patients recovered from respiratory distress within several days. However, small airway disease was still evident one year later. The other two, who were smokers, had only mild respiratory symptoms. These cases indicate that smoking may reduce the sensitivity to NO2. Further study is needed to elucidate the relationship between smoking and the severity of responses to NO2 inhalation.

[Detection of the trh gene in Vibrio parahaemolyticus isolated from overseas travellers' diarrhea and their biochemical characteristics]

A total of 478 Vibrio parahaemolyticus strains isolated from overseas travellers' diarrhea during the last 7 years of 1989 to 1995 were examined for the production of Kanagawa hemolysin by reversed passive latex agglutination (RPLA) test. Three hundred-seventy (77.4%) out of 478 strains were positive for Kanagawa hemolysin, whereas 108 strains were weakly positive or negative. For those Kanagawa hemolysin-weakly positive or negative strains, the tdh and trh genes associated with the production of TDH (thermostable direct hemolysin) and TRH (TDH-related hemolysin), respectively, were studied by the polymerase chain reaction method. The trh gene was detected in 98 (90.7%) out of 108 strains. In 35 strains belonging to 13 serotypes such as O3: K6, O1:K33, O3:K59, the trh gene alone was detected. On the other hand, both trh and tdh genes were detected in 63 strains of 17 serotypes including O1:K69, O3:K72, O6:K46. Among the strains of 4 serotypes including O1:K56, O1:KUT, O3:KUT and O5:KUT, two types of the trh positive alone and the trh and tdh positive were observed. Of interest, all of the 98 trh-positive strains were positive for the urease hydrolysis, whereas all Kanagawa hemolysin-positive strains were not. Furthermore, the strains of serotype O6:K18 (4 strains) were positive for the fermentation of dulcitol, and the strains of serotype O1:K1 (5 strains) were indole negative. These characteristics of the strains were completely different from those of typical V. parahaemolyticus strains.

NF-kappa B is induced in the nuclei of cultured rat aortic smooth muscle cells by stimulation of various growth factors

We investigated whether induction of transcription factor NF-kappa B is involved in the proliferation of cultured rat aortic smooth muscle cell using electrophoretic mobility shift assay and immunocytochemistry. NF-kappa B was induced in the nucleus in a dose-dependent manner when the smooth muscle cells were stimulated by various growth factors such as PDGF-BB, bFGF, EGF and IGF-1, but not growth inhibitors such as TGF-beta and IFN-gamma. Among growth factors, PDGF-BB and bFGF, more potent growth stimulators, induced higher kappa B binding activity than EGF or IGF-1. These evidences were also supported by the results obtained with immunocytochemistry. Immunocytochemistry also showed that the induced NF-kappa B contained p50 and p65. These results suggest that NF-kappa B induction may be involved in the proliferation of vascular smooth muscle cell.

[Characterization of Salmonella ser. enteritidis phage type 34 isolated from food poisoning outbreaks in Tokyo by epidemiological makers]

Since 1989, outbreaks of Salmonella ser. Enteritidis food poisoning has dramatically increased in Tokyo, and a total of 95 outbreaks has been reported between 1989 and 1993. As the results of examination of phage type by the method of Ward, et al., strains isolated from 31 (32.6%) of 95 outbreaks were phage type 34 which is a very rare type in Europe and America. To characterize these unique strains of phage type (PT) 34, 302 isolates obtained from patients and vehicle foods of the outbreaks, eggs and environments in Tokyo were examined for plasmid DNA profiles and antimicrobial resistance patterns. Plasmid DNA was extracted by the Kado's method, and analysed by agalose gel electrophoresis. Antimicrobial susceptibility was tested for CP, TC, SM, KM, ABPC, NA, SXT, FOM and NFLX by the K-B disc method. The strains of PT 34 were further subdivided to 4 types by plasmid profile and antibiogram. The prevalent pattern of PT 34 strains was type plasmid profile which carried 2 different plasmids (> 250 and 60 kb) and was streptomysin-resistant. A total of 28 (90.3%) of 31 outbreaks were found to be caused by this specific type of Salmonella ser. Enteritidis. Several kinds of egg-related foods were suspected for the vehicles of transmission among 12 outbreaks. Especially, in 5 outbreaks, this specific type (type B plasmid profile and streptomysin resistant) of Salmonella ser. Enteritidis strains were isolated both from patients and incriminated food which were cooked with eggs. The phase type of Salmonella ser. Enteritidis strains isolated from raw egg and poultry or environmental specimens from poultry farm showed that the prevailing phage types were almost the same as those of foods poisoning outbreaks. This strongly suggests that these foods may be considered as a source of infection in Salmonella ser. Enteritidis outbreaks.

Conversion of glutathione into cadystins and their analogs catalyzed by carboxypeptidase Y

Cadystins induced in a fission yeast treated with Cd2+ are the higher homologs of glutathione. In the present work, glutathione was incubated with Carboxypeptidase Y at a high substrate concentration. The reaction afforded not only the degraded product, but also cadystins and their analogs. A possible transformation pathway for glutathione by this enzyme is proposed.

Cervical spondylotic radiculopathy involving two adjacent nerve roots. Anterior decompression through a single level intervertebral approach

We describe a single level intervertebral approach to decompress two adjacent involved nerve roots in cases of cervical spondylosis. The operation was undertaken in 4 patients. We carried out discectomy, partial excision of the vertebral body with removal of the anteromedial part of the pedicles, removal of osteophytes and excision of the posterior longitudinal ligament, followed by an anterior interbody fusion. Fusion was achieved with the spine in normal lordosis and without complications. Pain and motor weakness was relieved in every case. This procedure can maintain movement at one additional disc level and has a better fusion rate than multilevel inter-body fusion.

The role of cell adhesion molecules in allograft rejection after penetrating keratoplasty in mice. Clinical and immunohistochemical study

BACKGROUND

It has been reported that adhesion molecules play an important role in immunological rejection after organ transplantation. In the present study, we examined the role of ICAM-1/ LFA-1 adhesion molecules in corneal allograft rejection and evaluated the immunological specificity of monoclonal antibodies (mAbs) in preventing allograft rejection in mice.

METHODS

The allografted mice were intraperitoneally injected with 100 micrograms/day of the following mAbs: a control mAb, anti-ICAM-1 mAb, anti-LFA-1 mAb, or a mixture of anti-ICAM-1 and anti-LFA-1 mAbs from 1 day before to 7 days after surgery. The expression of ICAM-1 and LFA-1 molecules in the grafted cornea was studied immunohistochemically. The corneas from a syngeneic donor or a third-party strain were transplanted 4 weeks after the initial keratoplasty onto the mice treated with both anti-ICAM-1 and anti-LFA-1 mAbs.

RESULTS

The allografts treated with anti-LFA-1 mAb alone or both anti-ICAM-1 and anti-LFA-1 mAbs remained transparent for more than 2 weeks, and the survival rate at 8 weeks was 40% in both groups. ICAM-1 was expressed on the mononuclear cells, keratocytes and endothelial cells in the allografts without treatment. The second corneal grafts syngeneic to the initial donor remained transparent at 2 weeks, whereas those from the third party were rejected.

CONCLUSIONS

ICAM-1 and LFA-1 adhesion molecules play a crucial role in the pathophysiology of corneal transplant rejection. The immunosuppressive effects of anti-ICAM-1 and anti-LFA-1 mAbs are highly allospecific. The administration of mAbs to the adhesion molecules represents a new means of suppressing allograft rejection after penetrating keratoplasty.

Effect of substrate on indirect immunofluorescence test for canine pemphigus foliaceus

The effect of substrate on indirect immunofluorescence (IIF) tests for the detection of circulating autoantibodies was studied by examining sera from 14 canine pemphigus foliaceus patients, six sera with non-pemphigus dermatoses and ten normal dog sera against five different substrates from three species. These substrates included bovine esophagus, bovine nose, bovine tongue, monkey esophagus, and canine nose skin. Nine out of 14 (64.3%) sera from patients with canine pemphigus foliaceus showed intercellular space staining by indirect immunofluorescence using bovine esophagus as substrate. However, sera from nonpemphigus dermatoses and normal dog did not react with bovine esophagus. In other substrates, only bovine tongue showed 1/8 (12.5%) positive reaction at the intercellular space by sera from canine pemphigus foliaceus. Dog nose skin showed the intercellular space staining against ten of ten (100%) normal dog serum. Monkey esophagus showed the fluorescent deposit at the intercellular space in four of nine (44.4%) of pemphigus foliacues dog sera, however, four of ten (40%) of normal dog sera revealed nonspecificity intercellular staining. These results indicate that the sensitivity and the specifity of IIF test in canine pemphigus foliaceus depend on the substrate. The best substrate for detecting circulating autoantibody in canine pemphigus foliaceus patients among five different substrates was bovine esophagus because of its sensitivity and high specificity. The diagnosis of canine pemphigus foliaceus should be made on the basis of a combination of clinical signs, histopathology, direct immunofluorescence, and the detection of circulating autoantibody.

Expression of TGF-beta type I and type II receptors in rat eyes

Transforming growth factor beta (TGF-beta) transduces signals through mediation of type I and type II serine/threonine kinase receptors. The expression of TGF-beta type I (T beta R-I) and II (T beta R-II) receptors in rat eyes was investigated immunohistochemically. T beta R-I and T beta R-II immunoreactivity was detected in corneal and conjunctival epithelial cells, corneal endothelial cells, ciliary epithelial cells, lens epithelial cells, retinal pigment epithelial cells, and choroidal vessels. This co-expression of T beta R-I and T beta R-II indicates that the above cells respond to TGF-beta and, because TGF-beta is reported to be produced in ocular tissues, that it may have important autocrine and/or paracrine roles in the growth and metabolism of ocular tissues in situ.

Histopathology of the liver in non-cirrhotic portal hypertension of unknown aetiology

Non-cirrhotic, long-standing portal hypertension of unknown aetiology is being re-evaluated histopathologically and clinically. In this study, we examined 107 livers with this condition (92 wedge biopsy and 15 autopsy specimens) from five institutions in Japan. These cases were histologically categorized into four groups: idiopathic portal hypertension (66 cases), nodular regenerative hyperplasia (14 cases), partial nodular transformation (two cases), and incomplete septal cirrhosis (25 cases). These four groups shared several histological features: dense portal fibrosis with portal venous obliteration and intralobular slender fibrosis. In addition, the histopathological features characteristic of one group were also found to a mild degree in other groups. The histopathological lesions preceding portal venous obliteration remain speculative. However, the portal venous obliteration may be responsible for the occurrence of sustained portal hypertension and several of the pathological changes in these livers. It seems likely that idiopathic portal hypertension, nodular regenerative hyperplasia, partial nodular transformation and incomplete septal cirrhosis comprise a family of non-cirrhotic, long-standing portal hypertension in Japan, and the histological differences between them may reflect chronological progression of a single disease.

Significance of the C-terminal domain of Erwinia uredovora ice nucleation-active protein (Ina U)

Ice nucleation-active (Ina) proteins of bacterial origin comprise three distinct domains, i.e., N-terminal (N-), central repeat (R-), and C-terminal (C-) domains, among which the R-domain is essential, and its length may be correlated with the ice nucleation activity. In addition, the short C-terminal domain of about 50 amino acid residues is indispensable for the activity. Using the Ina U protein of Erwinia uredovora, we carried out precise mutational analyses of its C-terminus. The ice nucleation activity (T50) assay showed that the C-terminal 12 amino acids were not necessary, and a deletion mutant (delta C29) with a new C-terminal, Met29 (numbered from the first amino acid residue of the C-domain and corresponding to Met1022), exhibited almost the same activity as the wild-type Ina U protein did. However, deletion of the C-terminal 13 residues including Met29 resulted in almost complete loss of the activity. In the deletion mutant (delta C29), amino acid replacement of the C-terminus, Met29, showed that the activity was retained when Met29 was replaced with a neutral, aromatic, or basic amino acid (Gly, Phe, or Lys), but was lost on the replacement with an acidic amino acid (Asp or Glu). In addition, two other residues in the C-terminal region commonly present in all Ina proteins were examined as to their importance, and it was shown that one of these residues, Tyr27, is important for the activity, although it is not exclusively required; the activity was lost to a great extent when this residue was replaced with Gly or Ala, but to a lesser extent when it was replaced with Leu. These results suggest that significance of the secondary and/or tertiary structure of the C-terminal region of the Ina U protein for the ice nucleation activity.

[Alterations of the brain stem and mid-latency evoked potentials under oxygen-nitrous oxide-sevoflurane anesthesia]

We evaluated the alterations of the brain stem and mid-latency evoked potentials (BAEP and MLAEP) in 10-patients who were scheduled for elective abdominal surgery under oxygen-nitrous oxide-sevoflurane anesthesia. With oxygen 2 l.min-1 and nitrous oxide 4 l.min-1, we measured the latency of BAEP and MLAEP at the end-expired sevoflurane concentrations of 0%, 0.3%, 0.6%, 1.0%, 1.5% and 2.0%, respectively. The latency of BAEP was slightly prolonged with oxygen-nitrous oxide-sevoflurane anesthesia. The latency of MLAEP was markedly prolonged with the increase of sevoflurane concentration, and all waves but Na wave disappeared at the 2.0% sevoflurane concentration.

A canine case of discoid lupus erythematosus with circulating autoantibody

A nine-year-old Shetland sheepdog was diagnosed as discoid lupus erythematosus by clinical features, histopathologic findings, positive direct immunofluorescence, negative antinuclear antigen test and the absence of multisystemic diseases. The indirect immunofluorescence test of this patient dog with the salt split skin showed the deposition at the bottom of the cleft at basement membrane zone (BMZ). Western immunoblotting revealed the 120 kDa and the 85 kDa proteins targeted by the autoantibody. These proteins did not correspond with the known BMZ component.

[Effects of blowing or aspiration on ablation rate by excimer laser]

Accurate calibration of ablation rate by excimer laser prerequisite for precise photorefractive keratectomy (PRK). When a polymethylmethacrylate (PMMA) plate is ablated by excimer laser, debris is generated, which may affect homogeneity of the laser beam and energy density, and change the ablation rate. In order to clarify the effects of the debris on the ablation rate, we studied the changes in the ablation rate when the debris was removed by blowing or aspirating over the ablation area during PRK.PMMA plates were ablated using a scanning excimer laser system (EC-5000, NIDEK, Japan) in PRK mode under the following conditions: (1) with air blowing over the ablation area, (2) with aspiration of the debris, and (3) without treatment. The ablation rates were determined by measuring the refractive power of PMMA plates with a lens meter. The ablated surface was observed by scanning electron microscope (SEM). The ablation rate with blowing was the highest among the three conditions, that with aspiration was the second, and that without treatment was the lowest. The ablation rates with blowing showed no significant change when the ablation rates were changed. However, the ablation rates with aspiration or without treatment decreased as the pulse rate increased. The surface ablated during blowing was the smoothest in SEM photographs. We concluded that calibration of the ablation rate using PMMA plates must be done with appropriate air blowing.

Abnormal T cell activation and skewed T cell receptor V beta repertoire usage in Japanese patients with idiopathic portal hypertension

Idiopathic portal hypertension (IPH), a disorder of unknown etiology, is characterized by a noncirrhotic portal hypertension associated with splenomegaly, hypersplenism, and anemia. We examined the surface phenotypes of T cells and the T cell receptor V beta repertoire in patients with IPH. The T cells in peripheral blood samples and from spleens showed a marked increase in frequencies of HLA-DP(+)- and HLA-DR(+)-activated T cells and the observed high frequencies in the blood were to a considerable extent reduced after splenectomy. Thus, the continuous activation of T cells may occur initially in the spleen. Investigation of T cell receptor V beta repertoire revealed a significant skewing of V beta 9 and V beta 11 in both peripheral blood and splenic T cells and V beta 12 in splenic T cells. The IPH may be a disease mediated by a continuous stimulation with either a certain antigen or more likely a superantigen.