Differential regulation of FGF-1 and -2 mitogenic activity is related to their kinetics of binding to heparan sulfate in MDA-MB-231 human breast cancer cells

The growth of the malignant human mammary MDA-MB-231 cells is stimulated by fibroblast growth factor-1 (FGF-1) but not by FGF-2. When these cells are cultured in the presence of chlorate, an inhibitor of heparan sulfate (HS) sulfation, their proliferation is stimulated by both FGF-1 and FGF-2. We analyzed the interactions of FGF-1 and FGF-2 with HS purified from the cell layer and the culture medium of control and chlorate-treated MDA-MB-231 cells. The HS from the cell layer bound FGF-1 with faster association kinetics than the HS from the culture medium, and so had a higher affinity for FGF-1. Chlorate treatment had no significant effect on the FGF-1 binding kinetics of the HS. In contrast to FGF-1, chlorate treatment of the cells significantly altered the FGF-2 binding kinetics. The HS from untreated cells possessed two binding sites for FGF-2, one with fast association kinetics (k(ass) 470,000 to 610,000 M(-1) s(-1)) and a high affinity (K(d) 46 to 70 nM) and one with slower association kinetics (k(ass) 74,000 to 100,000 M(-1) s(-1)) and a lower affinity (K(d) 290 to 400 nM). HS from chlorate-treated cells possessed just a single binding site for FGF-2 with fast association kinetics (k(ass) 270,000 to 290,000 M(-1) s(-1)) and a high affinity (K(d) 41 to 57 nM). These results show that there is a relationship between the binding kinetics of FGFs and their ability to stimulate cell growth.

Muscarinic regulation of basal versus thyrotropin-releasing hormone-induced prolactin secretion in rat anterior pituitary cells. differential roles of nitric oxide and intracellular calcium mobilization

Acetylcholine (ACh), synthesized in the pituitary, can act locally to modulate pituitary function. We used rat primary anterior pituitary (AP) cells to investigate how ACh affects pituitary prolactin (PRL) secretion in the presence or absence of known PRL regulators: thyrotropin-releasing hormone (TRH), 17beta-estradiol (E(2)) and triiodothyronine (T(3)). Cultured AP cells were prepared from ovariectomized rats and pretreated with diluent, 0.6 nM E(2), 10 nM T(3), or E(2) plus T(3) for 5 days, then challenged with various doses of ACh or muscarinic receptor agonists (oxotremorine or carbachol) and TRH (100 nM) for 20 min. Significant ACh (10(-5) M) suppression of both basal and TRH-induced PRL secretion was not evident in diluent-, E(2)- or T(3)-pretreated cells, but observed only in cells pretreated with both E(2) and T(3). Moreover, in E(2) plus T(3)-pretreated cells, oxotremorine and carbachol, like ACh (10(-7)-10(-5) M), suppressed both responses in a dose- related manner. Pertussis toxin (PTX; 100 ng/ml) as well as atropine (a muscarinic receptor antagonist; 1 mM) blocked these effects of cholinomimetics. ACh also inhibited both PRL responses elicited by drugs elevating intracellular cAMP (10 microM forskolin) or Ca(2+) (1 microM Bay K-8644) in a PTX-sensitive manner. ACh inhibition of basal PRL secretion was unaltered by intracellular Ca(2+) mobilization blockers, TMB-8 (100 microM) and thapsigargin (1 microM), but abrogated by the nitric oxide synthase inhibitor (300 microM L-NAME). ACh inhibition of TRH-induced PRL secretion was accentuated by TMB-8 and alleviated by thapsigargin or L-NAME. In summary, muscarinic inhibition of either basal or TRH-induced PRL secretion was augmented by E(2) and T(3), and involved the PTX-sensitive cAMP/Ca(2+) pathways. Furthermore, nitric oxide mediated the basal rather than TRH-induced PRL response to ACh, whereas the intracellular Ca(2+) mobilization concerned the TRH-induced rather than the basal PRL response to ACh. Thus, ACh synthesized in the AP appears to inhibit basal vs. TRH-induced PRL secretion via different mechanisms.

Changes of hepatitis B surface antigen variants in carrier children before and after universal vaccination in Taiwan

Mutants of a determinant of hepatitis B surface antigen (HBsAg) identified in vaccinated children pose a potential threat to long-term success of vaccination programs. We examined the mutants of a determinant (residues 110-160) of HBsAg in hepatitis B virus (HBV) DNA-positive children identified during previous serosurveys in Taipei undertaken just before (1984), 5 years after (1989), and 10 years after (1994) universal vaccination began. In HBV DNA-positive children from 3 surveys, the prevalence of a determinant mutants increased from 8 of 103 (7.8%) in 1984 to 10 of 51(19.6%) in 1989 and 9 of 32 (28.1%) in 1994 and was higher in those fully-vaccinated than unvaccinated (12/33 vs. 15/153, P =. 0003). Most amino acid changes of the variants clustered in residues 125-129 and 140-149. In all 27 children with detectable mutants, the mean age of those vaccinated was younger than those unvaccinated (4. 8 +/- 3.8 vs. 7.9 +/- 2.3 yrs, P <.05); and mutations occurred in a region with greatest local hydrophilicity (residues 140-149) more frequently in those vaccinated than in those unvaccinated (10/12 vs. 6/15, P =.0253). More mutated residues and more mutations at neutralizing epitopes, such as N146, C147, T148, and C149, were found in the 1994 survey. Vaccinated children may contract variant infections through vertical or horizontal transmission. Universal vaccination has accelerated an accumulation of HBsAg a determinant mutants with amino acid changes critical for immune escape in vaccinated children who became carriers, suggesting that new vaccination strategies should be considered.

Increased susceptibility to apoptosis of human hepatocarcinoma cells transfected with antisense N-acetylglucosaminyltransferase V cDNA

The antisense cDNA of N-acetylglucosaminyltransferase V (GnT-V, EC 2. 4.1.155) was constructed as pcDNA3/GnT-V-AS plasmid and transfected into 7721 cells, a human hepatocarcinoma cell line. The transfection was confirmed with Northern blot. By using HPLC and HRP-lectin staining, it was found that the cells transfected with pcDNA3/GnT-V-AS (GnT-V-AS/7721) expressed less GnT-V activity and beta-1,6-GlcNAc branching in the cell glycoproteins compared with the cells mock-transfected with the vector pcDNA3 (pcDNA3/7721). The growth rate of GnT-V-AS/7721 was decreased in serum-containing medium, while the cell death was accelerated in serum-free medium. The GnT-V-AS/7721 cells were more susceptible to the apoptosis induced by ATRA than the mock-transfected cells. This was evidenced by the obvious appearance of a hypoploid sub-G(1) fraction in the DNA histogram using FCM analysis, the more condensed new moon-type nuclei under morphological observation, and the more intensive TUNEL reaction for assaying the fragmented DNA. At the same time as GnT-V down-regulation by GnT-V-AS, an increase of another N-aceylglusaminyltransferase, GnT-III (EC 2.4.1.144), was observed, and the biological significance of this finding was discussed.

Cutaneous lymphocyte antigen is expressed on memory/effector B cells in the peripheral blood and monocytoid B cells in the lymphoid tissues

Cutaneous lymphocyte antigen (CLA) is expressed on a subpopulation of human memory T cells and is involved in the primary step of their skin homing. T cells and some B cells in the peripheral blood express CLA, but the pathophysiologic roles of CLA(+) B cells have not yet been clarified. We examined the relationships among CLA expression in B cells and immunoglobulin heavy chain subtype, the localization of CLA(+) B cells in the peripheral lymphoid tissues, and their functional binding to E-selectin. CLA was expressed on class-switched, memory B cells in the peripheral blood and tonsils as revealed by flow cytometry. Immunohistochemical staining of the lymph nodes with various types of inflammation or reactive hyperplasia showed CLA on the monocytoid B cells, which correspond to memory cells. The functional study revealed that CLA on B cells bound to E-selectin transfectants. E-selectin was detected on some of the high endothelial venules in the monocytoid B-cell-rich lymph nodes. These findings suggest that CLA is also expressed on a subset of memory/effector B cells, in addition to a subset of memory T cells. Such B cells were located in the lymph nodes or tonsils and rarely in chronic dermatitis. Therefore, CLA seems to be related to memory/effector B-cell trafficking to the lymph nodes or tonsils. According to the multistep theory, mechanisms involved in the second or third step might be different between CLA(+) B and T cells.

Thrombocytosis in children at one medical center of southern Taiwan

Thrombocytosis in children is common, but usually without symptoms. The causes of thrombocytosis in children are considered to be mostly due to infection, trauma, surgery, blood disease, prematurity, renal disease and chronic inflammation. To evaluate the incidence and etiology of thrombocytosis of the hospitalized patients, patients who were admitted to the Pediatric Department of Kaohsiung Medical College Hospital (KMCH) from October 1996 to November 1997 were studied. There were 2910 cases studied and 220 cases (127 male and 93 female) had thrombocytosis (> or = 500 x 10(9)/L) with a rate of 7.6%. The causes of thrombocytosis are infections (49.5%), Kawasaki disease (6.4%), postsplenectomy (7.8%), blood diseases (3.7%), malignancies (3.2%), renal disorders (3.2%), prematurity (3.2%), tissue damage (4.5%), chronic inflammation (1.8%), recovery from marrow suppression (1.3%), immunologic disturbances (2.2%), essential thrombocythemia (0.5%), and miscellaneous factors (3.7%). Thrombocytosis associated with multiple, simultaneous causative factors was found in 9.0% of these cases. Thrombocytosis secondary to infectious diseases or Kawasaki disease was significantly more common in children under 2 years old. The most commonly associated infectious disease was respiratory tract infection (61.1%). There were 29 children (13.2%) presenting a platelet count of more than 800,000/mm3. However, no thrombotic complications were seen in any of the children. By far, the major cause of thrombocytosis in our cases was reactive in character. Most of the thrombocytosis cases were due to infections, inflammatory diseases, or Kawasaki disease.

Alterations in glycosyltransferases during myeloid and monocytoid differentiation of HL-60 cells

HL-60, a human promyelocytic leukemia cell line, can be differentiated to myeloid lineage by all- trans retinoic acid (ATRA), dimethylsulfoxide (DMSO) and n -butyric acid (n -BA), or to monocytoid(monocytic/macrophagic) lineage by phorbol-12-myristate-13-acetate (PMA) and ganglioside GM(3). The activity alterations of N -acetylglucosaminyltransferase III and V (GnT-III, GnT-V) as well as alpha-1,6-fucosyl-tranferase (alpha1,6 Fuc T) were studied during the differentiation of HL-60 cells by the above-mentioned five inducers using the fluorescence (PA)-labeled glycan-HPLC method for GnT assays and biotin-labeled glycan-LCA affinity chromatography combined with the HRP-avidin colorimetric method for alpha1,6 Fuc T assay. It was observed that after 3 days, all three enzymes decreased in HL-60 cells induced by 1 micromol/l ATRA and 0.6 mmol/l n-BA, while GnT-III and alpha1,6 Fuc T increased, but GnT-V still decreased after induction by 1% DMSO. GnT-V and alpha1,6 Fuc T declined, while GnT-III was elevated after induction by 0.1 micromol/l PMA for 3 days. In contrast, GnT-III increased after the treatment with 50 micromol/l GM(3)for 3 or 6 days, but GnT-V was not appreciably changed and alpha1,6 FucT was elevated after 6 days of GM(3)treatment. It may be concluded that the decrease of GnT-V is the common change in myeloid differentiation and the increase of GnT-III is the general alteration in monocytoid differentiation. The changes in the activities of glycosyltransferases were consistent with the structural changes in surface N -glycans previously found in our laboratory, i.e. that the antennary number of N -glycans decreased during myeloid differentiation by ATRA, and the amount of bisecting GlcNAc in N -glycans increased during monocytoid differentiation by PMA.

Hexamethyldisiloxane film as the bottom antireflective coating layer for ArF excimer laser lithography

We demonstrate a new bottom antireflective coating (BARC) layer for ArF excimer laser lithography. The antireflective layer is composed of hexamethyldisiloxane (HMDSO) film, which is deposited by the conventional electron cyclotron resonance-plasma-enhanced chemical-vapor deposition process. We obtain the appropriate HMDSO films for BARC layers by varying the gas-flow rate ratio of oxygen to HMDSO. Such a process has several advantages: high deposition rate, low process temperature, easy film removal, and reduced cost. Measured reflectances of less than 0.5% on both Al-Si and silicon crystal substrates have been achieved and agree well with the simulated reflectances. The swing effect is shown to be significantly reduced by addition of the HMDSO-based BARC layer.

Cyno-EBV (EBV-related herpesvirus from cynomolgus macaques) induces rabbit malignant lymphomas and their tumor cell lines frequently show specific chromosomal abnormalities

Malignant lymphoma (ML) induction in rabbits by Epstein-Barr virus (EBV)-related herpesvirus of cynomolgus (Cyno-EBV) is reported. Twenty-seven of 30 (90%) rabbits inoculated intravenously with Cyno-EBV-producing simian (cynomolgus) lymphocyte cell line (Ts-B6) cells developed ML between 45 and 115 days after inoculation. The peroral inoculation of Ts-B6 cells induced ML in only 2 of 10 (20%) rabbits (75 to 85 days). Five of 6 (83%) rabbits injected with cell-free pellets from Ts-B6 cultures also developed ML (27 to 122 days). Antibody response to the viral capsid antigen of EBV was also detected in sera from rabbits inoculated with Ts-B6. ML of the large cell or mixed type infiltrated diffusely in many organs, frequently involving the spleen, liver, kidneys, heart, and less frequently the lungs, lymph nodes, brain, eyes, gastrointestinal tract, thymus, and bone marrow. A chromosomal analysis of five lymphoma cell lines established from tumor-bearing rabbits revealed the rabbit karyotype. Three of these cell lines showed the chromosomal abnormalities with 12q- or t (7p+:12q-). EBV-encoded small RNA-1 and EBV-associated nuclear antigen 1 were expressed in Ts-B6 cells, the tumor tissues, and all rabbit cell lines by in situ hybridization and by immunofluorescence tests, respectively. EBV DNA was also detected in Ts-B6 cells and rabbit lymphoma cell lines by polymerase chain reaction and Southern blot analysis. The Southern blots of EBV termini revealed oligoclonal bands in the Cyno-EBV-induced rabbit lymphomas. No lymphoma was induced by the inoculation of B95-8 (EBV-producing cells) or peripheral leukocytes from normal cynomolgus (controls). These data suggest that the high rate of lymphoma induction in rabbits may be caused not by human EBV (B95-8) but by Cyno-EBV from Ts-B6 cells. A sequence analysis of the IR1 (BamHIW) region of Cyno-EBV revealed that this region is quite similar to that of herpesvirus Macaca fascicularis 1, which is a causative agent for a monkey model of AIDS-related lymphomas. The present rabbit model of lymphoma with specific chromosomal abnormalities is very useful to clarify the role of EBV in human EBV-associated lymphoma and provides a means for studying prophylactic and therapeutic regimens.

Interference coatings based on synthesized silicon nitride

Silicon nitrides are synthesized by ion-assisted deposition with only one coating material and a nitrogen-ion-beam source. All the SiN(x) films are amorphous and mechanically strong. A wide range of refractive indices from 3.43 to 1.72 at a wavelength of 1550 nm is obtained. Near-IR antireflection coating and a bandpass filter based on the multilayers of SiN(x) and Si are demonstrated.

Primary sclerosing cholangitis in a child

Primary sclerosing cholangitis (PSC) is a rare disease in Taiwan and has not been described in Taiwanese children previously. We report a 4-year-old girl who presented with prolonged fever, eosinophilia (11%), hepatomegaly, and markedly elevated serum levels of alkaline phosphatase (3,318 IU/L) and gamma-glutamyl transpeptidase (475 IU/L). Subsequent investigations including endoscopic retrograde cholangiopancreatography and liver histology confirmed the diagnosis fo PSC. Treatment with a low dose of prednisolone for 2 months and ursodeoxycholic acid during 32 months of follow-up resulted in clinical remission and halted disease progression. A high index of suspicion is necessary for physicians to diagnose this disorder in children with chronic liver disease. Our experience in this case indicates that therapy with prednisolone and ursodeoxycholic acid may be helpful for the treatment of PSC in children, and suggests the need for more trials of combined therapy.

[Molecular typing of Taiwanese Orientia tsutsugamushi isolates by restriction fragment profile]

Scrub typhus, which is caused by Orientia tsutsugamushi, is one of the reportable diseases in Taiwan, ROC. Positive cases seemed to be increasing in recent years and our laboratory had confirmed a total of 247 cases in 1997. In this study, 71 strains of O. tsutsugamushi were isolated from heparinized blood of the patients by cell culture, and their DNA was isolated. Two-step polymerase chain reaction was then used to amplify a specific sequence from the DNA, which was digested with restriction enzymes, Hha I and Sfa NI, for typing. With this technique, 34 strains gave rise to the same profile as that of the Kuroki type, 6 as the Karp type and 2 as the Gilliam type. The remaining 28 strains produced fragment profiles different from those of types Karp, Kato, Kawasaki, Kuroki, Gilliam and Shimokoshi and, therefore, were classified as 6 new types designated Taiwan A to Taiwan F, respectively. These strains with profiles different from those of the standard Japanese strains may represent the local mutant strains.

[Immunohistochemical study of the expression of fucosylated glycoconjugates in human lung carcinoma]

Lewis X, Sialyl Lewis X and Sialyl Dimeric Lewis X are three fucosylated glycoconjugates on cell surface. With immunohistochemical method, the expression of the three structures in the original lung cancer tissues (with or without metastasis), adjacent tissues and metastatic lesions of lung carcinoma were studied. It was found that the three antigens were expressed with different intensity on the cell surface and in the cytoplasm of the lung carcinoma cell. However, there was no or only trace expression of these antigens in the adjacent tissues of lung carcinoma and normal lung tissues. Moreover, the original lesions of lung carcinoma with metastasis and/or poor differentiation expressed higher level of the three antigens than those without metastasis and/or with well or medium differentiation. Sialyl Lewis X was considered to be more closely related to the metastatic ability and differentiation of the lung carcinoma cell than the other two antigens, Lewis X and Sialyl Dimeric Lewis X. Furthermore, in the lymph nodes with lung carcinoma cell metastasis, there were expression of the three antigens with different degree, while in those lymph nodes without lung carcinoma cell metastasis, there was no expression of the three antigens.

Differential reactivity of the rat S100A4(p9Ka) gene to sodium bisulfite is associated with differential levels of the S100A4 (p9Ka) mRNA in rat mammary epithelial cells

Elevated intracellular levels of S100A4, an S100-related calcium-binding protein, induce metastatic capability in benign mammary tumor-derived epithelial cells and in transgenic mice bearing oncogene-induced benign mammary tumors. The S100A4(p9Ka) gene in rat mammary epithelial cells expressing low levels of S100A4 yields a reduced number of fragments upon digestion with the methylation-sensitive restriction enzyme, HpaII, compared with the gene from high S100A4-expressing cells. Genomic sequencing of two potential regulatory elements in the S100A4 gene, an intronic enhancer and TATA box region, revealed that in low S100A4-expressing cells, most cytosine bases exhibited high levels of resistance to conversion to thymine by sodium bisulfite. In derivative cell lines, which express high levels of S100A4, only a small number of cytosine bases were resistant to treatment with sodium bisulfite. In contrast, cytosine bases in the DNA surrounding an upstream regulatory region, which binds inhibitory GC factor in the low-expressing cell lines, are sensitive to conversion to thymine by sodium bisulfite in both low- and high-expressing cell lines. The results suggest that the rat S100A4 gene is maintained in a different state in the low-expressing cell lines and that this state might be a consequence of the pattern of methylation in this regulated gene that does not contain a CpG island.

Alteration in transcripting the gene encoding the delta-opioid receptor in rat brain is not underlying the development of tolerance to [D-Ala2,D-Leu5] enkephalin

Previous study has demonstrated that chronic treatment of [D-Ala2,D-Leu5] enkephalin (DADLE) induces profound down-regulation of delta opioid receptor in rat brain. We further examined whether this down-regulation of receptor was due to a decrease in the transcription of gene encoding delta-opioid receptor (DOR-1). Rats received daily i.c.v. injection of DADLE for 1, 3, or 5 days and developed significant tolerance to the antinociceptive effect of DADLE after one-day treatment. We measured the level of mRNA in rat brain tissues using in situ hybridization. No significant changes in the mRNA levels of the cortex, striatum, hippocampus, and thalamus on any examined days were found as compared to those of rats received sham operation only. There is only a transient decrease of DOR-1 mRNA level in midbrain region that occurred after a three-day treatment. Thus, the result of this study did not suggest that alteration in transcription of gene-encoding delta-opioid receptor was responsible for the down-regulation of delta-opioid receptor associated with the development of tolerance to DADLE.

[Changes with cell cycle of N-acetylglucosaminyl transferase III, IV and V in 7721 human hepatocarcinoma cells]

In order to investigate the changes of N-acetylglucosaminyl transferase (GlcNAc-T) III, IV and V in cell cycle, the synchronization of 7721 human hepatocellular carcinoma cells was performed using serum hunger method. The percentages of cells in different phases during cell cycle were measured by flow cytometry (FCM) and the cell cycle was checked by determining the activity of cellular p34cdc2 kinase. It was found that the activities of GlcNAc-T III increased in G0/G1 cell peak phase and had correlation with the cell percentage of G0/G1 phase (r = 0.760, P < 0.05), while GlcNAc-T V showed the highest activity when G2/M cells were most abundant and had an apparent correlation with the cell percentage of G2/M phase (r = 0.868, P < 0.001). The changes of GlcNAc-T IV activity seemed not related to the cell cycle. The changes in opposite directions of relative activities (percentage of total GlcNAc-T III, IV, V) of GlcNAc-T III and GlcNAc-T V were observed during cell cycle (r = -0.951, P < 0.001), suggesting that these two enzymes might be regulated differently and functioned oppositely in the cells: GlcNAc-T V may be related to the proliferation of 7721 cells, while GlcNAc-T III may be related to the non-mitotic silence phase of the cells, or, it may be a factor against proliferation. Immunohistochemical results showed that the protein content of GlcNAc-T V was not significantly changed during cell cycle, and had no correlation with the activity of GlcNAc-T V, suggesting that the changes of GlcNAc-T V activity in cell cycle might not be resulted from the alteration of enzyme protein synthesis. The correlation between the activities of GlcNAc-T V and p34cdc2 kinase (r = 0.752, P < 0.05) was observed in cell cycle, implicating that GlcNAc-T V might possibly be regulated by p34cdc2 kinase.

[Effects of sex hormones on the expression of placenta form glutathione S-transferase (GST-P) in rat induced hepatocarcinoma]

Using Solt-Farber method for the induction of rat hepatocarcinoma, the changes of the activity of glutathione S-transferase (GST) and the content of placenta form GST (GST-P) were studied during hepatocarcinogenesis, then the effects of sex hormones on the hepatic expression of GST-P were observed using immunohistochemical method. The results showed that both GST activity and GST-P content began to increase at the 3rd week, and reached the highest level at the 5th week (Table 1). Therefore, the 5th week was selected for the study of GST-P expression in the livers of rats treated with different protocol (Fig. 1). It was found that GST-P was highly expressed in the livers of sham-castrated male rats after chemically induced hepatocarcinoma (PLATE I, Fig. 1A, Table 2). When estradiol was administrated to these rats, both the number and area of GST-P positive(+) foci decreased significantly (PLATE I, Fig. 1B, Table 2). While testosterone was administrated instead of estradiol, the decrease of the area but slight increase of the number of GST-P positive foci were found (PLATE I, Fig. 1C, Table 2). After orchiectomy, the areas of GST-P (+) foci in carcinogen treated liver of male rats were smaller than those in rats with sham-orchiectomy and same carcinogen treatment (PLATE I, Fig. 2A, B, Table 3). When the orchiectomized male rats were administrated with estradiol, the areas of GST-P (+) foci decreased further (PLATE I, Fig. 2C, Table 3). In contrast, after ovariectomy of the female rats, the areas of GST-P (+) foci in carcinogen treated livers were slightly increased as compared with those in the rats with sham-ovariectomy and same carcinogen treatment (PLATE I, Fig. 2D, E, Table 3). While the ovariectomized female rats were administrated with testosterone, the areas of GST-P (+) foci increased further (PLATE I, Fig. 2F, Table 3). Regardless of whether castrations were done or not, GST-P expression in livers of male rats induced hepatocarcinoma was higher than in livers of female rats (PLATE I, Fig. 2A, B, D, E, Table 3). These results indicated that estrogen may inhibit but androgen may promote the GST-P expression in the rat liver during hepatocarcinogenesis. This may be related to the higher incidence of liver carcinoma in male than in female.

Television and music video exposure and risk of adolescent alcohol use

OBJECTIVE

Alcohol use is frequently portrayed in television programming and advertising. Exposure to media portrayals of alcohol use may lead to increased drinking. To address this issue, we examined prospectively the associations between media exposure and alcohol use in adolescents.

DESIGN

Prospective cohort study. Setting. Six public high schools in San Jose, California. Participants. Ninth-grade students (N = 1533; mean age = 14.6 years).

OUTCOME MEASURES

Students reported hours of television, music video, and videotape viewing; computer and video game use; and lifetime and past 30 days' alcohol use at baseline and 18 months later. Associations between baseline media exposure and subsequent alcohol use were examined with multiple logistic regression.

RESULTS

During the 18-month follow-up, 36.2% of baseline nondrinkers began drinking and 50.7% of baseline drinkers continued to drink. Onset of drinking was significantly associated with baseline hours of television viewing (odds ratio [OR] = 1.09; 95% confidence interval [95% CI] = 1.01-1.18), music video viewing (OR = 1.31; 95% CI = 1. 17-1.47), and videotape viewing (OR = 0.89; 95% CI = 0.79-0.99), controlling for age, sex, ethnicity, and other media use. Computer and video game use was not significantly associated with the subsequent onset of drinking. Among baseline drinkers, there were no significant associations between baseline media use and maintenance of drinking.

CONCLUSIONS

Increased television and music video viewing are risk factors for the onset of alcohol use in adolescents. Attempts to prevent adolescent alcohol use should address the adverse influences of alcohol use in the media.

Mixed medullary-follicular carcinoma and papillary carcinoma of the same thyroid

We report a rare case of mixed medullary-follicular carcinoma and papillary carcinoma of the same thyroid. A 27-year-old Chinese female complained of a single thyroid nodule for 2-3 months. Needle aspiration revealed suspicious papillary carcinoma and thyroidectomy performed later showed mixed medullary-follicular carcinoma and papillary carcinoma of the same thyroid which was extremely rare. Whether neoplastic transformation is due to tumorigenic stimulus or just due to the collision phenomenon is still controversial for its etiology.

Development and evaluation of an Epstein-Barr virus (EBV) immunoglobulin M enzyme-linked immunosorbent assay based on the 18-kilodalton matrix protein for diagnosis of primary EBV infection

A new immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) based on the recombinant Epstein-Barr virus (EBV) matrix protein was developed. Compared to indirect immunofluorescence for the detection of IgM antibody to the EBV capsid antigen on clinical specimens, the sensitivity and specificity of the new IgM ELISA were 96 and 96%, respectively.

Long-term culture of hepatocytes from human adults

A long-term primary human hepatocyte culture retraining liver-specific functions is important and essential for basic research and for the future development of hepatocyte-based applications. We established a normal hepatocyte culture system from excess normal tissues obtained from adult liver cancer patients who received partial liver resection. Hepatocytes were isolated after perfusion and enzymatic disaggregation, and were first maintained in hormonally defined media on a Matrigel matrix, and then transferred to collagen sandwich gel. The hepatocytes formed clusters on the Matrigel matrix and increased in size and numbers with time of culture and eventually grew into spheroids of variable sizes. After being transferred to collagen gel, the cells migrated outward from spheroids to form a monolayer with cuboidal or polygonal cell shapes with granular cytoplasm and continued to proliferate. Cellular functions specific for hepatocytes were analyzed using immunoblot assay for proteins specifically secreted by the liver cells on different days of culture. The cells secreted albumin, transferrin and alpha-fetoprotein consistently for more than 100 days, to a maximum of 150 days. Thus, we have established a long-term culture of hepatocytes from human adults, which will be useful for basic studies of liver physiology such as metabolism and morphogenesis, as well as for other applications in the study of infectious hepatitis, pharmacology, pharmacokinetics, and toxicology.

Alteration of N-acetylglucosaminyltransferases in pancreatic carcinoma

The activities of three N-acetylglucosaminyltransferases (GnT III, GnT IV and GnT V) were determined in 10 samples of pancreatic carcinoma (PCa) and compared with those in 9 samples of normal pancreatic tissue (NP). It was found that the specific activities of GnT III, GnT IV and GnT V increased in all of the PCa samples. GnT III increased most significantly, up to 22.3 fold of normal, GnT IV was elevated 12.3 fold, while GnT V increased only 2.4 fold. The elevation of GnTs in pancreatic carcinoma was consistent with the increase in the number of antenna and bisecting GlcNAc structures in N-glycans of pancreatic ribonuclease (RNase) as assessed by Con A affinity chromatography. Polycytidylate specific RNase from the serum of PCa patients showed the same structural changes as that found in in N-glycans of the RNase from PCa tissue.

Antibodies to E2 protein of hepatitis G virus in children: different responses according to age at infection

OBJECTIVES

To study viral persistence and antibody responses after hepatitis G virus (HGV) infection in children of various ages.

STUDY DESIGN

We performed an enzyme immunoassay for antibodies to E2 protein (anti-E2) of HGV and reverse-transcription polymerase chain reaction assay for HGV RNA on serum samples.

RESULTS

Of 28 infants born to HGV RNA-positive mothers, 17 were found to be positive for HGV RNA. None were positive for anti-E2. All 17 infected infants continued to have viremia except 1 who converted to HGV RNA-negative status at 24 months. Six infants had mild elevations of alanine aminotransferase levels (5 HGV-positive and 1 HGV-negative). An additional 14 HGV-infected children (aged 6 months to 14 years) with posttransfusion HGV infection were tested for anti-E2 3 months and 12 months after blood transfusion. None of the HGV RNA-positive serum samples were positive for anti-E2; however, 4 of the 8 children with resolving HGV infection were positive for anti-E2 1 year later.

CONCLUSIONS

Mother-to-infant transmission of HGV resulted in a high viral persistence rate and lack of immune responses to HGV. In contrast, anti-E2 appeared in children who recovered from posttransfusion HGV infection. Mode of transmission and age at infection may be important factors in determining persistent HGV infection and defective immune response to HGV.

Mechanisms by which wheat bran and oat bran increase stool weight in humans

Generally, stool weight is significantly increased by adding sources of insoluble fiber to the diet. Comparable amounts of fiber provided by wheat and oat brans have the same effect on daily stool output, even though > 90% of wheat bran fiber but only 50-60% of oat bran fiber is insoluble. To determine the bases for these increases in stool weight, stool samples collected from 5 men in 2 constant diet studies that determined the effects of wheat and oat brans on large-bowel physiology were fractionated by using a physicochemical procedure into plant, bacterial, and soluble fractions, which were weighed and analyzed for sugar content and composition. Nitrogen, crude fat, and ash outputs were also determined. Wheat bran increased the fecal concentration of sugars and mass of plant material more than did oat bran, whereas oat bran increased fecal bacterial mass more. Each fiber source increased nitrogen, ash, and fat excretion, but excretion of fat was greater with oat bran. The apparent digestibility of plant-derived neutral sugars decreased significantly when wheat but not oat bran was consumed. The apparent digestibility of neutral sugars provided by wheat bran was 56%; the apparent digestibility of those provided by oat bran was 96%. We conclude that bacteria and lipids are major contributors to the increase in stool weight with oat bran consumption, whereas undigested plant fiber is responsible for much of the increase in stool weight with wheat bran consumption. Results are consistent with the hypothesis that oat bran increases stool weight by providing rapidly fermented soluble fiber in the proximal colon for bacterial growth, which is sustained until excretion by fermentation of the insoluble fiber.

Modification of pentasaccharide core of surface N-glycans during differentiation of HL-60 cells

All-trans retinoic acid (ATRA) or phorbol-12-myristate-13-acetate (PMA) are two representative inducers which induce the differentiation of HL-60 cells to myelocytes and monocytes respectively. Structural modifications of the pentasaccharide core portion of N-glycans on cell surface glycoproteins during differentiation of HL-60 cells induced by these two agents and the enzymatic mechanism of the structural modifications were studied. Both ATRA and PMA enhanced the incorporation of [3H]-labeled mannose into N-glycans of glycoproteins from cell surface. By using E-PHA and WGA lectin affinity chromatography to analyze [3H]-N-glycans prepared from the surface of control, ATRA- and PMA-treated cells, it was found that the content of bisecting GlcNAc (bis-GlcNAc) attached to the core of N-glycans decreased in ATRA-treated cells, but increased in PMA-treated cells. Since GlcNAc T-III is the enzyme responsible for the synthesis of bis-GlcNAc, the change of bis-GlcNAc was consistent with the alteration of GlcNAc T-III activities in ATRA- and PMA-treated cells. Core alpha-1,6 fucose of surface N-glycans decreased during differentiation which was determined by AAL affinity chromatography. This was also compatible with the reduced activity of alpha-1,6 Fuc T. the enzyme catalyzing the synthesis of core Fuc, in ATRA- and PMA-treated cells. The increase of GlcNAc T-III activity and bis-GlcNAc content in N-glycans may be related to cell adhesion observed in monocytic differentiation.