Abnormalities of primitive myeloid progenitor cells expressing granulocyte colony-stimulating factor receptor in patients with severe congenital neutropenia

To define the basis for faulty granulopoiesis in patients with severe congenital neutropenia (SCN), the expression of granulocyte colony-stimulating factor receptor (G-CSFR) in primitive myeloid progenitor cells and their responsiveness to hematopoietic factors were studied. Flow cytometric analysis of bone marrow cells based on the expression of CD34, Kit receptor, and G-CSFR demonstrated a reduced frequency of CD34(+)/Kit(+)/ G-CSFR(+) cells in patients with SCN. The granulocyte-macrophage colony formation of CD34(+)/Kit(+)/G-CSFR(+) cells in patients was markedly decreased in response to G-CSF alone and to the combination of stem cell factor, the ligand for flk2/flt3, and IL-3 with or without G-CSF in serum-deprived semisolid culture. In contrast, no difference in the responsiveness of CD34(+)/Kit(+)/G-CSFR(-) cells was noted between patients with SCN and subjects without SCN. These results demonstrate that the presence of qualitative and quantitative abnormalities of primitive myeloid progenitor cells expressing G-CSFR may play an important role in the impairment of granulopoiesis in patients with SCN. (Blood. 2000;96:4366-4369)

Adhesion in vitro of oral streptococci to porcelain, composite resin cement and human enamel

We investigated the initial adhesion in vitro of oral streptococci to porcelain inlays. Four strains of streptococci, Streptococcus mitis NCTC12261, Streptococcus oralis ATCC9811, Streptococcus sanguis ATCC10556 and Streptococcus sobrinus OMZ176, were used in this study. The disc specimens were made of porcelain, composite resin cement and human enamel. These specimens, with or without a saliva-coat, were immersed in a suspension of each streptococci strain at 37 degrees C for 1 hr, and the numbers of cells adhering to specimens were counted after staining. The saliva-coat significantly decreased the numbers of adhering cells in all strains tested (t-test, p < 0.05). The adhesion to the porcelain and resin cements could be explained by a thermodynamic approach, although the adhesion to enamel could not be explained. These results indicated the possibility that the mechanism is different in initial adhered strains of streptococci between enamel and dental restorative materials.

Corticosteroid pretreatment prevents small intestinal mucosal lesion induced by acetic acid-perfusion model in rats

One of the important problems in experimentally induced small intestinal lesions is that there is no reproducible model of diffuse and stable mucosal lesion. In this paper, we studied in detail the effects of continuous perfusion of various concentrations of acetic acid on the rat small intestinal mucosa. In order to evaluate its applicability for screening of the preventive effect of drugs on gut damage, we also evaluated the efficacy of corticosteroid pretreatment in preventing acetic acid-induced mucosal lesion. Male Sprague-Dawley rats were fasted for 12 hr, and the small intestinal lumen was perfused with 1%, 1.5%, 2.5%, 3%, 3.75% (pH 2.4-2.6) acetic acid or saline (control) at 1 ml/min for 15 min. In separate experiments, the effect of preadministration of budesonide (0.5 or 0.75 mg/kg/day) and prednisone (0.75 mg/kg/day) on 1.5% acetic acid-induced mucosal damage was investigated. Macroscopic and microscopic lesions occurred diffusely in a concentration-dependent fashion. Histological findings revealed signs of transmural inflammation characterized by mucosal-submucosal edema, ulceration, and neutrophil infiltration. Mucosal-submucosal height had an inverse relation with the acetic acid concentrations perfused. Myeloperoxidase activity levels increased several-fold in the acetic acid-perfused groups. Corticosteroid pretreatment prevented microscopic damage and was associated with reduction of MPO activity levels in 1.5% acetic acid-perfused rats. We conclude that this simple and reproducible model could be applied for the screening of new drugs in the gastrointestinal tract in which large numbers of animals are taken into account.

Expression of intrapulmonary surfactant apoprotein-A in autopsied lungs: comparative study of cases with or without pulmonary hypoplasia

To investigate the functional maturity of the lungs of infants with pulmonary hypoplasia, we measured the expression of surfactant apoprotein-A (SP-A) in the autopsied lungs. Autopsied lungs were taken from 16 infants who died at birth or soon after. A lung-to-body weight ratio of less than 1.2% was defined as pulmonary hypoplasia. Eight infants were classified as belonging to the normal group, and eight as belonging to the pulmonary hypoplasia group. Many of the pulmonary hypoplasia group were complicated not only by pulmonary hypoplasia, but also by amniotic fluid volume abnormalities or an anatomical malformation. We measured the expression of SP-A immunologically using murine anti-human SP-A MAb in the autopsied lung tissue, and subjected the tissue to SP-A staining by the direct staining method. The expression of SP-A was assessed as one of four grades: -, +/-, 1+, 2+. The staining intensity of SP-A was high at 1+ or stronger in five infants of the normal group. SP-A expression was significantly reduced, however, in all infants of the pulmonary hypoplasia group except for one infant with normal amniotic fluid volume and relatively mild pulmonary hypoplasia. There was a significant negative correlation between the staining intensity of SP-A and two factors: pulmonary hypoplasia and abnormal amniotic fluid volume (p = 0.039 and p = 0.0063, respectively). In the present study, we demonstrated that SP-A expression was significantly reduced in infants with pulmonary hypoplasia. We speculate that the functional maturity of the lungs of infants with pulmonary hypoplasia is also suppressed.

Epigenetic alterations in methylation in oral squamous cell carcinoma cell lines detected by two-dimensional gel electrophoresis

It has been described that DNA alterations in human oral squamous cell carcinomas were successfully demonstrated as 6 spots being commonly reduced in more than 50% of 10 lesions using the restriction landmark genomic scanning (RLGS) method. In the present study, the question of whether the DNA alterations involve not only genetic but also epigenetic change was examined with the use of cell lines Ca9-22, HO-1-u-1, HSC-2 and KB and treatment with a demethylating agent 5-aza-2'-deoxycytidine (5-AzaCDR). Intensities of two of the reduced spots were amplified in the cell lines by the 5-AzaCDR treatment, showing that they were due to altered DNA methylation. Our study provides clear evidence that epigenetic changes, like the methylation are related to carcinogenesis in human oral squamous cell epithelium.

[Species and serovar-distribution, and drug-resistance of Shigella strains isolated from imported and domestic cases during 1995-1999 in Tokyo]

A total of 290 Shigella strains consisting of 180 imported strains and 110 domestic strains isolated during 1995-1999 in Tokyo were examined regarding their species and serovar-distribution and their drug-resistance. In both groups, S. sonnei (70.0% in the imported strains, 80.9% in the domestic strains) was found to be the most prevalent species, followed by S. flexneri (20.0% in the imported strains, 19.1% in the domestic strains). S. dysenteriae and S. boydii were only isolated in the imported cases. Among the S. flexneri serovar, 1b, 2a, 6, 2b, and 3a were predominant in the imported strains, whereas 1b and 2a were predominant in the domestic strains. Provisional new serovar Shigella strains were isolated from 11 imported cases and 2 domestic cases. The drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM, and NFLX) showed that 92.2% of the imported strains and 94.5% of the domestic strains were resistant to some of the drugs tested. Drug-resistance patterns of the resistant strains varied in 25 types. Among those, a triple drug-resistance type with TC.SM.ST was found as the most frequent pattern in both groups. None of the strains were resistant to NFLX.

Effects of cyclosporin A on water-immersion stress-induced gastric lesion and gastric secretion in rats

Cyclosporin A is an immunosuppressive agent which is well known as a specific inhibitor of calcineurin (protein phosphatase 2B). In this study, we investigated the effects of cyclosporin A on water-immersion stress-induced gastric ulcer formation and gastric acid secretion in rats. We also examined the localization of calcineurin immunohistochemically. Calcineurin was specifically expressed in gastric parietal cells and chief cells of the gastric mucosa. The intraperitoneal administration of cyclosporin A dose-dependently suppressed the development of gastric mucosal lesions induced by water-immersion stress and inhibited gastric acid secretion, as assessed by pylorus ligation. These results indicated that calcineurin may play an important role in gastric acid secretion.

Bullous eruption associated with scabies: evidence for scabetic induction of true bullous pemphigoid

Some patients with scabies develop bullae concomitantly with, or subsequently after, the occurrence of scabetic lesions. Although several immunofluorescence studies have demonstrated immunoglobulin deposition in the basement membrane zone of bullous lesions, it remained unclear whether these antibodies are directed to bullous pemphigoid antigens. We clearly show that two scabetic patients with bullous eruptions had circulating antibodies against BP180 and/or BP230 as determined by Western blotting analysis. This is the first report to demonstrate that at least some of the bullous eruptions occurring in scabetics are true bullous pemphigoid.

Insulin and insulin-like growth factor I support the proliferation of erythroid progenitor cells in bone marrow through the sharing of receptors

The effects of insulin and insulin-like growth factor I (IGF-I) on the proliferation of erythroid progenitor cells in bone marrow were studied in serum-deprived culture. Primitive human bone marrow cells were purified by cell sorting on the basis of the expression of CD34 and the Kit receptor. Insulin and IGF-I with erythropoietin (EPO) dose dependently supported the formation of erythroid colonies of CD34+/Kit+ cells in bone marrow. The direct effect of insulin and IGF-I on the stimulation of primitive erythroid progenitor cells was confirmed by single-cell proliferation studies in serum-deprived liquid suspension culture. The addition of insulin and/or IGF-I to stem cell factor (SCF) resulted in an additive increase in the number of erythroid colonies. The erythroid colonies formed by insulin and IGF-I with EPO were different in size from those formed by SCF with EPO. These findings imply that erythroid progenitor cells responding to insulin and IGF-I might be at a different developmental stage of erythropoiesis from those responding to SCF in CD34+/Kit+ cells. Similarly, insulin and IGF-I with EPO supported the proliferation of the mature erythroid progenitor cells in light-density bone marrow mononuclear cells (LDBMCs). The addition of the anti-receptor antibody to IGF-I receptor or insulin receptor partially suppressed erythroid colony formation supported with insulin or IGF-I in both CD34+/Kit+ cells and LDBMCs. The simultaneous addition of both receptor antibodies completely abrogated the erythroid colony formation. These results suggest that insulin and IGF-I directly stimulate the proliferation of the late stage of primitive erythroid progenitor cells and mature erythroid progenitor cells through the sharing of receptors.

[Increasing nalidixic-acid-resistance in Salmonella strains isolated from sporadic cases in Tokyo]

A total of 118 nalidixic-acid (NA)-resistant Salmonella strains consisting of 68 domestic strains and 50 imported strains isolated during 1988-1998 in Tokyo were examined regarding their annual incidence, serovars, drug-resistance patterns, and minimum inhibitory concentrations(MIC) to fluoroquinolones (NFLX, OFLX, ENX, and CPFX). NA-resistant strains accounted for 1.3% of all Salmonella (5,302 strains) isolated from domestic cases, and 2.5% of all Salmonella (1,981 strains) isolated from imported cases. The incidence of NA-resistant strains has increased since 1995, and it has been remarkable in imported cases. The results of the serotyping showed that the NA-resistant strains were classified into 25 serovars, excluding untypable strains. Among those, S. Enteritidis (21 strains), S. Blockley (13 strains), S. Litchifield (13 strains), S. Typhimurium (13 strains), S. Hadar (9 strains), and S. Virchow (8 strains) were predominant. Drug-resistance patterns of NA-resistant strains, including other drugs (CP, TC, SM, KM, ABPC, ST, FOM, and NFLX) tested varied among the 26 types. Among those, multidrug-resistant strains accounted for 61.9% (73 strains), and one strain among them was high-resistant to NFLX. MIC distribution of NA-resistant strains to fluoroquinolones showed that the ranges of all drugs were 4-128 times higher than NA-sensitive strains used for controls.

Genomic DNA analyses of spontaneous hepatocellular carcinomas in LEC rat liver using a new technique

An inbred rat strain, LEC (long evans cinnamon) has been used as a model of human Wilson's disease. This animal suffers from a severe type of hepatitis, the clinical manifestations of which are similar to human fulminant hepatitis for 4-5 months which is caused by accumulation of copper in the liver. The surviving rats develop chronic hepatitis, followed by the development of spontaneous hepatoma. In contrast to studies with hepatocellular carcinomas (HCCs), the studies have great advantages in that the animals have identical genetic background, can be raised under a fixed condition, and the development of HCC is reproducible. We took two HCC samples and analysed their genomic DNA using RLGS (restriction landmark genomic scanning), which involves two-dimensional electrophoresis of genomic DNA allowing the survey of some 1,000 NotI sites throughout the genome. Using this technique, we discovered landmark spots that were either decreased or increased in intensity in HCC and compared them with the RLGS profile obtained from the DNA of control normal LEC rat liver. Approximately 1,300 spots were compared, and the intensity of two spots was found to be decreased about half and one was increased 1.3-1.7 folds. Although the mechanism of these changes and the properties of the changed DNA are yet to be studied, recurrent genomic changes in the LEC rat HCC could prove to be a good model system for elucidating the essential genetic events in association with hepatocarcinogenesis.

ELISA for a complexed antigen with a monoclonal antibody blocking reaction with the free antigen-assay-specific for complexed prostate-specific antigen

We have developed an enzyme-linked immunoassay (ELISA) for serum complexed-antigen (prostate-specific antigen; PSA)(c-PSA) with simultaneous blocking of free-antigen (PSA)(f-PSA). The assay utilizes three different monoclonal antibodies (MAbs) recognising three distinct PSA epitopes. The detection limit was established as 0.19 microg/l (n=20, mean of zero standard+2S.D.) and the average recovery of f-PSA was 98-100%. The within-run and between-day coefficients of variation (CV) ranged from 2.1% to 3.2% and 2.8% to 6.3%, respectively. There was a good correlation between serum c-PSA measured by the present ELISA and PSA-alpha(1)-antichymotrypsin complex (PSA-ACT) concentrations (r=0.991). This method should provide a better tool for discriminating between benign and malignant prostatic disease.

Analysis of prognostic and survival factors related to treatment of low-grade astrocytomas in adults

Prognostic factors for low-grade astrocytomas have been proposed, but optimal treatment remains controversial. Eighty-eight consecutive adult patients with supratentorial low-grade astrocytomas were retrospectively reviewed to determine specific factors influencing outcome. All underwent craniotomy (43 radical resections, 45 nonradical resections). Sex, age at diagnosis, preoperative Karnofsky performance status (KPS), tumor location, estimated extent of resection, radiation, chemotherapy, histological type, p53 status, MIB-1 staining and the apoptotic index were assessed as parameters for prognostic significance. KPS (p = 0.03), tumor location (p < 0.001), extent of surgical resection (p < 0.001) and radiotherapy (p = 0.01) were significantly associated with longer survival rates by univariate analysis. Multivariate analysis also showed a significant correlation between radiation therapy after surgical removal and survival time (p < 0.001). p53 status was not of importance in determining the necessity for radiotherapy. Radical surgical removal is the most important factor in the management of low-grade astrocytomas. Radiation therapy appears to be effective in improving the prognosis regardless of the extent of surgical resection or the p53 status.

Defective proliferation of primitive myeloid progenitor cells in patients with severe congenital neutropenia

Although several mechanisms have been proposed to explain the pathophysiology of severe congenital neutropenia (SCN), the precise defect responsible for SCN remains unknown. We studied the responsiveness of primitive myeloid progenitor cells to hematopoietic factors in 4 patients with SCN. The number of granulocyte-macrophage (GM) colonies formed in patients was decreased in response to granulocyte colony-stimulating factor (G-CSF) in both serum-supplemented and serum-deprived culture. The polymerase chain reaction-single-strand conformational polymorphism analysis of the G-CSF receptor gene showed no variance in structure conformation between the 4 patients and the normal subjects. In patients with SCN, the nonadherent light density bone marrow cells and cells that were purified on the basis of the expression of CD34 and Kit receptor (CD34(+)/Kit(+) cells) showed the reduced response to the combination of steel factor (SF), the ligand for flk2/flt3 (FL), and interleukin-3 (IL-3) with or without G-CSF in serum-deprived culture. Furthermore, when individual CD34(+)/Kit(+) cells from patients were cultured in the presence of SF, FL, and IL-3, with or without G-CSF for 10 days, the number of clones proliferated and the number of cells per each proliferating clone was significantly less than those in normal subjects. These results suggest that primitive myeloid progenitor cells of patients with SCN have defective responsiveness to not only G-CSF, but also the early- or intermediate-acting hematopoietic factors, SF, FL, and IL-3.

Influence of filler content and gap dimension on wear resistance of resin composite luting cements around a CAD/CAM ceramic inlay restoration

We investigated the influence of filler content and gap dimension on the wear resistance of composite luting cement around CAD/CAM ceramic inlay restorations. Experimental hybrid dual-cured composite luting cements containing 60, 70, 72, 74 and 80 wt% of silanated barium-silica fillers were used for cementing CAD/CAM ceramic inlay into the cavity. The specimens involving inlay-cement-tooth interfaces were subjected to a three-body wear test. The relation between the interfacial gap dimension and wear loss was also investigated using 60, 70 and 80 wt% filled cements. The cements containing more than 70 wt% filler presented significantly higher wear resistance than 60 wt% filled cement. There was a positive linear relationship between gap dimension and wear loss, and the inclination of the regression line decreased with increasing filler content. These results indicated that the higher filler content of the cement increased the wear resistance and this desirable influence appeared more remarkably in the wider horizontal gap dimension.

[Incidence of Salmonella serovar Hadar from sporadic cases in Tokyo, and drug resistance of isolates]

A total of 780 Salmonella serovar Hadar (S. Hadar) strains consisting of 601 domestic strains and 179 imported strains isolated in Tokyo, 1980-1998, were examined regarding their incidence and drug-resistance. Domestic strains accounted for 7.2% of all Salmonella (8,359 strains) isolated from domestic cases, and imported strains accounted for 4.4% of all Salmonella (4,083 strains) isolated from imported cases. A drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOR, and NFLX) showed that 586 strains (97.6%) of the domestic strains and 175 strains (97.8%) of the imported strains were resistant to some of the drugs, excluding NFLX. Drugs with a high resistance rate were TC and SM for both groups. Drug-resistance patterns of the resistant strains varied among the 24 types. Among those, prevalent patterns recognized were TC.SM.KM (231 strains), TC.SM (205 strains), and TC.SM.KM.ABPC (65 strains) in the domestic strains, and TC.SM (135 strains) and TC (13 strains) in the imported strains.

[Outbreak case caused by different colicin type of Shigella sonnei in a day nursery in Tokyo (1998)]

From October through December, 1998, person to person infection caused by Shigella sonnei had occurred in the day nursery in Hachioji-city Tokyo, and a total of 41 patients including 3 suspected cases and 3 carriers had been confirmed. Although one case was imported case which is one-year-old kindergarten child, the remaining was domestic case. Of patients, 33 cases (80.5%) were a three-year-old kindergarten children and their families, accounting for 20 and 13 cases, respectively. From the data of symptom onset of patients, epidemic could distinguish to the former part and the later part. The recur or reinfection, and re-detection case was observed in the later part. Clinical symptom of the patients was diarrhea (100%), fever (80%) and abdominal cramps (70%), and LVFX for adult or FOM for child was used for the therapy. In the colicin typing test and the antibiotic susceptibility test for 9 reagents, almost isolates in the former part were type 0 and susceptible, and MBC for FOM ranged from 6.25 to 100 micrograms/ml, whereas those in the later part was type 2 and resistant for the TC, and showed highly MBC for FOM with 50 or 100 micrograms/ml. However, both isolates showed same patterns in plasmid profiles and DNA fingerprints by RAPD analysis. On the other hand, the strain from imported case was also colicin 0, but it was different as regards resistant for ABPC and ST and two genetic analysis.

[Drug-resistance and definitive type 104 of Salmonella serovar typhimurium isolated from sporadic cases in Tokyo, 1980-1998]

A total of 674 Salmonella serovar Typhimurium (S. Typhimurium) strains consisting of 522 domestic strains and 152 imported strains isolated in Tokyo, 1980-1998, were examined regarding their drug-resistance and phage-type. Domestic strains accounted for 6.2% of all Salmonella (8,359 strains) isolated from domestic cases, and imported strains accounted for 3.7% of all Salmonella (4,083 strains) isolated from imported cases. A drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM, and NFLX) showed that 245 strains (46.9%) of the domestic strains and 109 strains (71.7%) of the imported strains were resistant to some of the drugs, excluding FOM and NFLX. Drugs with a high resistance rate were TC, SM, ABPC, and CP for both groups. Drug-resistance patterns of the resistant strains varied among the 40 types. Among those, prevalent patterns recognized were CP.TC.SM.ABPC, CP.TC.SM.KM.ABPC, TC.SM, SM, and TC.KM in the domestic strains, and TC, CP.TC.SM.ABPC, CP.TC.SM.KM.ABPC, CP.TC.SM.KM.ABPC.ST and TC.KM in the imported strains. The results of the phage-typing test revealed that 31 strains of 52 domestic strains tested, and 13 strains of 46 imported strains tested were definitive type 104 (DT104). Those resistance patterns were CP.TC.SM.ABPC.SU (43 strains) and CP.TC.SM.KM.ABPC.SU (1 strain).

Carcinogenic effects of N-ethyl-N-hydroxyethylnitrosamine and its metabolites in rats and mice

N-ethyl-N-hydroxyethylnitrosamine (EHEN), a member of the nitrosamine class of carcinogens induces renal cancer. However, since very little is known about the metabolic products of EHEN and their effects, these were investigated in rats and mice. EHEN, N-ethyl-N-formylmethylnitrosamine (EFMN) and N-ethyl-N-carboxymethyl-nitrosamine (ECMN) were administered in the drinking water for 2 weeks and the animals were then maintained until sacrifice at week 32. The urine of the rats was collected over the 2-week exposure period and analyzed by HPLC. The results showed that EHEN but not EFMN or ECMN induces tumors in the kidneys of rats. In mice the lungs were targeted not only by the parent compound but also by both metabolites. The findings suggest that the kidney is the most susceptible organ to EHEN effects in the rat while the lung is the most susceptible organ in mice. These results are consistent with inter-species variation in the metabolism of xenobiotics.

Artificial caries removal and inhibition of artificial secondary caries by pulsed CO2 laser irradiation

PURPOSE

To investigate the inhibition of artifical secondary caries around restorations placed after removal of artificial caries by pulsed CO2 laser irradiation and by mechanical means.

MATERIALS & METHODS

Beveled cavities were prepared mechanically on the facial surfaces of extracted human molars. Each cavity was subsequently exposed to an artificial caries (demineralizing) solution (pH 5.0) for 7 d to generate a demineralized zone approximately 100-200 microns thick on the cavity surface. The artificial carious/demineralized zones of the cavities were removed by a pulsed CO2 laser operating at a wavelength of 9.3 microns with pulse duration of 100 microseconds and an irradiation intensity of 5 J/cm2. Artificial control caries were removed mechanically with a carbide bur in a slow speed handpiece. The cavities were slightly undercut and restored with a resin-based composite without etching and bonding and the restored teeth were subjected to pH cycling solutions for 10 d as follows: Demineralization solution, pH 4.5 for 6 hrs, followed by remineralization solution, pH 7.0 for 18 hrs. Cycled teeth were sectioned through the restorations and the resulting lesions were analyzed in thin section using polarized light and Knoop microhardness.

RESULTS

Mean microhardness delta Z values, indicating mineral loss were: 549 (SD 191) for control, and 140 (SD 127) N = 11. This difference is significant with t = 5.543 and P = 0.000 (Paired t-test). Caries penetration: Control side--231 microns (SD 71), Laser treated side: 123 microns (SD 79) N = 6. This difference is significant with t = 5.198 and P = 0.003 (Paired t-test). The results show that the laser treatment not only removed artificial caries, but also inhibited decalcification of the cavity wall in a subsequent artificial caries challenge by as much as 81% compared to control samples. No etching and bonding was used in this pilot study, which might have influenced the results. Future studies should address the inhibition effect of the laser treatment as compared to adhesive techniques, fluoride treatments and fluoride release restorative materials.

CONCLUSION

Caries removal by a pulsed lambda = 9.3 microns CO2 laser produces a cavity surface morphology with marked resistance to artificial secondary caries as compared to mechanical removal.

Immunohistochemical analysis of midkine expression in human prostate carcinoma

Midkine (MK) is a growth/differentiation factor frequently expressed at high levels in some types of human malignancies. To investigate whether MK is a useful marker in prostate carcinogenesis, immunohistochemical analysis was performed on samples of both latent and clinical prostate cancers of various stages, as well as on specimens of normal gland and prostatic intraepithelial neoplasia (PIN). Of the 80 clinical cancers examined, 69 specimens (86.3%) were immunoreactive for MK, with metastatic lesions generally showing higher expression than the corresponding primaries; normal prostate tissues were negative or showed only weak staining. Midkine was also detected in 12 of 15 latent cancers (80%) and in 12 of 16 cases of PIN (75%). In sections of whole prostate, MK showed variable expression through tumorous sections, probably in reflection of heterogeneous cell populations. The results demonstrate the possible value of MK as a marker for early and latent disease, as well as for more advanced clinical stages of prostate cancer.

A novel sperm-specific hypomethylation sequence is a demethylation hotspot in human hepatocellular carcinomas

Certain human DNA regions are strikingly undermethylated at CpG sites in sperm compared to adult somatic tissues. These sperm-specific hypomethylation sequences are thought to function early in embryogenesis or gametogenesis. By using the restriction landmark genomic scanning (RLGS) cloning method, we have isolated a novel sperm-specific hypomethylation sequence, the status of which changes during spermatogenesis, embryonal growth and differentiation. This sequence is a part of a new 'NotI repeat' consisting of a 1.4 kb repetitive unit sequence named DE-1. The sequence is GC-rich and has high homology to a CpG DNA clone that was isolated by a methyl CpG protein binding column, indicating that it was normally highly methylated. We investigated the methylation status of this sequence. In the normal genome the sequence was methylated, but in the human hepatocellular carcinoma (HCC) genome, the target sequence was demethylated at the cytosine residue of the CpG dinucleotides with high frequency (75% in the previous study). These data suggest that this regional DNA hypomethylation may play a role in both cell differentiation and hepatocarcinogenesis.

Genomic alterations in human meningiomas detected by restriction landmark genomic scanning and immunohistochemical studies

Using restriction landmark genomic scanning (RLGS) methods, 21 samples of human meningioma were analyzed. We found 3 alterations in the genomic DNAs of tumor samples located on chromosomes 5, 14 and 17 which appear to be common to the meningothelial subtype. Two other separate genetic abnormalities located on chromosomes 9-12 and 20 are apparently associated with atypical meningiomas. In addition, the neurofibromatosis type 2 gene is apparently involved in more than half of the tumor samples. There appear to be both common and type-specific genetic mutations associated with the formation and progression of human meningiomas.

Isolation of NotI clusters hypomethylated in HBV-integrated hepatocellular carcinomas by two-dimensional electrophoresis

To examine genetic and epigenetic alterations associated with HBV integration in hepatocarcinogenesis, we compared genomic DNA profiles of primary hepatocellular carcinomas (HCCs) and cell lines that either contained or did not contain integrated HBV. To accomplish this, we carried out Restriction Landmark Genomic Scanning (RLGS), a two-dimensional system that displays 2000-3000 Not I landmark sites in a single gel electrophoresis experiment. We identified one Not I landmark spot that showed high signal intensity in HBV-integrated cell lines or in primary HCCs, but not in HCCs or tumor-cell lines free of HBV integration. Cloning of this spot revealed that it consisted of a Not I cluster sequence enriched with CpG dinucleotides. This sequence, hypomethylated in association with HBV integration, was found in the peri-centromeric region of human acrochromosomes. The results demonstrate that epigenetic changes at specific sequences in the genome occur in association with HBV integration during the process of hepatocarcinogenesis.

Structure and enzymatic properties of genetically truncated forms of the water-insoluble glucan-synthesizing glucosyltransferase from Streptococcus sobrinus

Glucosyltransferase-I (GTF-I: 175 kDa) of a cariogenic bacterium, Streptococcus sobrinus 6715, mediates the conversion of water-soluble dextran (alpha-1,6-glucan) into a water-insoluble form by making numerous alpha-1,3-glucan branches along the dextran chains with sucrose as the glucosyl donor. The structures and catalytic properties were compared for two GTF-I fragments, GTF-I' (138 kDa) and GS (110 kDa). Both lack the N-terminal 84 residues of GTF-I. While GTF-I' still contains four of the six C-terminal repeats characteristic of streptococcal glucosyltransferases, GS lacks all of them. Electron microscopy of negatively stained samples indicated a double-domain structure for GTF-I', consisting of a spherical head with a smaller spherical tail, which was occasionally seen as a long extension. GS was seen just as the head portion of GTF-I'. In the absence of dextran, both fragments simply hydrolyzed sucrose with similar K(m) and k(cat) values at low concentrations (<5 mM). At higher sucrose concentrations (>10 mM), however, GTF-I' exhibited glucosyl transfer activity to form insoluble alpha-1, 3-glucans. So did GS, but less efficiently. Dextran increased the rate and efficiency of the glucosyl transfer by GTF-I'. On removal of the C-terminal repeats of GTF-I' by mild trypsin treatment, this dextran-stimulated transfer was completely lost and the dextran-independent transfer became less efficient. These results indicate that the N-terminal two-thirds of the GTF-I sequence are organized as a structurally and functionally independent domain to catalyze not only sucrose hydrolysis but also glucosyl transfer to form alpha-1,3-glucan chains, although not efficiently; the C-terminal repeat increases the efficiency of the intrinsic glucosyl transfer by the N-terminal domain as well as rendering the whole molecule primer-dependent for far more efficient insoluble glucan synthesis.