A human hepatocellular carcinoma cell line with multiple copies of structurally normal chromosomes

At Veterans General Hospital (VGH), a cell line, HA59T(HA59T/VGH), was established from a primary hepatocellular carcinoma of a 52-year-old Chinese male patient. G-banded metaphases were analyzed at passages 12 and 62. Of the 200 cells counted, 68% had 100-110 chromosomes/cell at passage 12, and 74% had 90-100 chromosomes/cell at passage 62. The presence of multiple copies of a structurally normal chromosome in a single cell was common for most of the chromosomes. Both X and Y sex chromosomes were normally present in the majority of the cells. This cell line is karyotypically different from those reported in other literature.

Effect of pancreas allografts on the ultrastructure of sciatic nerves in diabetic rats

In a long-term study using cyclosporin-A (Cy-A) as immunosuppressant in a dose of 10 mg/kg/day, pancreas-duodenum was transplanted from Brown-Norway donors to alloxan-diabetic Lewis rats (n = 190). The pancreas transplants (PT) were performed after 1, 3, 6, 9, 12, and 15 months of diabetes. Recipient rats were sacrificed between 3 and 12 months of graft retainment. The mean axonal cross-sectional area and relative percentage of small, medium, and large myelinated fibers was evaluated. Also studied were unmyelinated fiber, ovoid body, and glycogen inclusion densities. Control rats consisted of non-diabetic rats (n = 36), similar rats receiving Cy-A (n = 42), diabetic rats (n = 103), and diabetic rats receiving Cy-A (n = 45). It was found that PT had a beneficial effect on the axonal cross-sectional area of myelinated nerves, the relative percentage of the various sizes of nerve fibers, and the ovoid body density, especially so in early diabetes. The effects in late diabetes were less spectacular. PT did not prove beneficial to the glycogen inclusion and unmyelinated fiber densities.

Chemotherapy in nasopharyngeal carcinoma: review of results at University Hospital, Kuala Lumpur

Nasopharyngeal carcinoma (NPC) is one of the commonest presentation of head and neck cancers in Malaysia, especially in the Chinese. The standard treatment is radical radiotherapy to the post-nasal space and the neck. Chemotherapy is given to patients with primary advanced disease and to patients with recurrence. The study reviews results of chemotherapy given to 33 patients at the University Hospital, Kuala Lumpur, over the last four years.

Insulin suppresses hepatitis B surface antigen expression in human hepatoma cells

The human hepatoma Hep3B cells contain integrated hepatitis B viral genome and continually secret hepatitis B surface antigen (HBsAg). The production of HBsAg (but not alpha-fetoprotein) was suppressed by addition of low concentrations (0.1-1 nM) of insulin into serum-free medium. In addition, the suppression of HBsAg production by insulin was paralleled with the decrease in HBsAg mRNA abundance. Insulin also cause a rapid rate of disappearance of HBsAg mRNA (t 1/2, 2 h) in Hep3B cells. The Hep3B cells carry specific receptor with high affinity for insulin (Kd = 1.8 nM). The receptor showed an insulin-dependent protein tyrosine kinase activity. The half-maximal insulin concentration for the activation of the receptor kinase was about 5 nM. Only very high concentrations of insulin-like growth factor I and human proinsulin can compete for the insulin receptor binding and suppress HBsAg production, this suggests that insulin may act through its receptor binding to suppress HBsAg expression in human hepatoma Hep3B cells.

Hepatitis B virus transcript produced by RNA splicing

A new hepatitis B virus (HBV) transcript of about 2.2 kilobases was identified in HBV DNA-transfected human hepatoma cells. The 5' terminus of this viral RNA appears to map at one or more of the precore initiation sites, contains a deletion of 1,223 bases corresponding to the last codon of the core gene to the middle of the surface antigen gene, and terminates at the 3' polyadenylation site used by the other known HBV RNAs. The junction region of the deleted sequences showed the conserved splice donor and acceptor GT-AG sequences. Moreover, when a mutant HBV DNA in which the splice acceptor site was changed from AG to CG was transfected into human hepatoma cells, no 2.2-kilobase RNA was detected, further suggesting that this RNA represents a spliced transcript. The core gene, although an amino acid shorter, still encoded a functional viral core protein in complementation experiments. Sequence analysis of the cDNA of the 2.2-kilobase RNA suggests that this transcript can potentially encode a new protein that comprises the reverse transcriptase domain of HBV. However, genetic analysis using a transient DNA transfection system suggests that the gene product(s) of this transcript is not essential for viral replication. The function of this transcript remains to be studied.

Cytomegalovirus enhances lysis of HIV-infected T lymphoblasts

A T4+ lymphoblastoid cell line (CR-10) persistently infected with the human immunodeficiency virus (HIV) and designated CR-10/NIT was superinfected with cytomegalovirus (CMV) isolated from peripheral blood mononuclear cells of a patient with AIDS. A productive CMV cycle in the CR-10/NIT lymphoblasts was demonstrated by fluorescent antibody staining (IF) using a monoclonal antibody (MAb) to the 150-kDa major capsid protein, by infectivity assays and by electron microscopy (EM). Two-color IF analysis showed that a small percentage of the CR-10/NIT cells were producing both CMV and HIV at any one time. EM studies revealed that all doubly infected cells were lysed whereas most cells infected only with HIV appeared intact. Cell lysis appeared 24 hr after superinfection of the CR-10/NIT cells with CMV and progressed to complete destruction of the cell culture between days 9 and 10. Our results suggest that CMV may convert a mildly cytopathic HIV infection of T lymphoblasts into a highly lytic process.

Type I familial amyloid polyneuropathy in a Chinese family

A Chinese family with at least 3 members having the typical clinical picture of type I familial amyloid polyneuropathy is presented. The pathological features, including the immunohistochemical typing of the amyloid deposits, are described and the literature is briefly reviewed.

Expression of class I and class II major histocompatibility antigens on human hepatocellular carcinoma

Previous reports indicate that human hepatocytes do not express class I and class II MHC antigens. Our analyses on 10 human hepatocellular carcinoma (HCC) cell lines by immunofluorescence tests and RIA, demonstrate that all the human HCC cell lines tested express class I MHC antigens and among them, three poorly differentiated human HCC cell lines also express class II MHC antigens. Results of immunoprecipitation and/or Western blotting experiments indicate similarity in the chemical nature of both the class I and class II MHC antigens expressed by the human HCC cell lines and by a human B lymphoblastoid cell line Raji. Furthermore, a new variant form of class I antigen was detected in some of these HCC cell lines. Immunohistochemical studies of HCC tissues using the peroxidase-antiperoxidase staining method indicated that class I and class II antigens were detectable in 7 out of 11 and 3 out of 11 HCC tissues from patients, respectively. The availability of MHC class I antigen-positive cultured HCC cell lines, including the poorly differentiated lines that also express MHC class II antigen, has provided us with interesting models to study the relationship between expression of MHC antigen and transformation and differentiation of human hepatocytes. These studies will also allow us some insight into the role of MHC class I and class II antigen in the immunosensitivity and immunogenicity of HCC cells to the host-immune response.

Subcortical arteriosclerotic encephalopathy--a controlled psychometric study

Eleven patients with subcortical arteriosclerotic encephalopathy (SAE) were assessed psychometrically, and the results compared with control subjects without neurological disorders and patients with a single cerebral vascular lesion (CVL). The groups were matched for sex, age, years of education, and in addition for the CVL group, the nature, site and size of the discrete vascular lesion. The SAE patients had mild to moderate impairment in intellectual, memory, receptive language and constructional functions, but individual performance ranged from near normality to severe impairment. The differences between the performance of SAE patients and the controls were significant in the majority of tests. The SAE patients had lower scores than CVL patients on all tests, but in many of these the difference was not significant.

Visualization of membrane-associated folate transport proteins

Transport of Methotrexate (MTX) into cells, via the "reduced folate" transport system, is a critical factor in the effectiveness of the drug in cancer chemotherapy, and defective transport is one of the principal types of resistance to MTX. Probes capable of detecting membrane-associated folate transport proteins (ftp's) in individual cells are potentially useful for identifying structural and functional domains and for investigating mechanisms of substrate translocation. Polyclonal antibody to highly purified ftp from Lactobacillus casei, in conjunction with a second, gold-labeled antibody, has been used to visualize, via electron microscopy, the protein in Triton-treated membrane fragments and in the membrane and cytoplasm of spheroplasts. To visualize ftp in L1210 cells, the substrate-binding site was first labeled covalently with activated fluorescein-Methotrexate, and the cells were then treated with anti-fluorescein antibody and the gold-labeled antibody.

The human liver glutathione S-transferase gene superfamily: expression and chromosome mapping of an Hb subunit cDNA

We have isolated from a lambda gt10 cDNA library a clone lambda GTH4 which encodes a human liver glutathione S-transferase Hb subunit, designated as subunit 4. Expression of this cDNA in E. coli and subsequent purification and immunoblotting analysis provided a definitive assignment of a structure and function relationship. RNA blot hybridization with human liver poly(A) RNA revealed a single band of approximately 1200 nucleotides, comparable in size to the rat brain Yb3 mRNA. Divergence analysis of amino acid replacement sites in subunit 4 relative to the four rat Yb subunits revealed that it is most closely related to the brain-specific Yb3 subunit. This conclusion is further substantiated by the nucleotide sequence homology between lambda GTH4 and the Yb3 cDNA in their 3' untranslated region. In situ chromosome mapping has located this glutathione S-transferase gene in the region of p31 on chromosome 1. Results from many laboratories, including ours, indicate that the human glutathione S-transferases are encoded by a gene superfamily which is located on at least two different chromosomes.

Natural and activated cytotoxic lymphocytes reactivity to human hepatocellular carcinoma cell lines in hepatocellular carcinoma patients

The status of cellular cytotoxic activity in Hepatocellular Carcinoma (HCC) patients was compared to that in normal individuals by testing the cytotoxicity against K562 and five established HCC cell line targets. Natural killer (NK) activity of fresh peripheral blood mononuclear (PBM) cells in HCC patients to K562 cell line target was lower than that in normal donors. NK activity of unstimulated PBM cells from either source was minute against all five HCC cell line targets. Three different activation systems were employed to examine the cellular cytotoxicity of activated PBM cells: (1) conventional mixed lymphocyte culture (MLC), (2) allogeneic mixed lymphocyte tumor culture (MLTC), and (3) lymphokine-activated killer (LAK) cell culture. The cytotoxic effects of PBM cells in all three activation conditions were significantly lower in HCC patients than in normal donors (P less than 0.05 to P less than 0.01). These results suggest that, in addition to naturally present NK cells, the degree of in vitro activation of PBM cells may also have decreased in HCC patients.

Expression of oncogenes in human hepatoma cell lines

The expression of 20 known cellular proto-oncogenes in human well-differentiated hepatoma cell line Hep3B and poorly-differentiated hepatoma cell line HA22T/VGH was studied by Northern blot hybridization. Among the cellular proto-oncogenes examined, both cell lines express protein kinase genes including fps, mos and raf; PDGF B chain sis gene; GTP/GDP binding protein gene Ha-ras and nuclear protein genes including fos and myc. The expression of yes, abl, ros, src, erb-B, erb-A, fms, Ki-ras, myb, rel and bas genes was not detected in both cell lines.

Nuclear antigens reacted with sera and ascites of hepatocellular carcinoma patients

In order to study hepatocellular carcinoma-associated antigens, screening of sera and ascites was done from hepatocellular carcinoma patients having antibodies reactive with three hepatocellular carcinoma cell lines (PLC/PRF/5, Hep 3B and HA22T/VGH). The indirect immunofluorescent antibody test was used. Ten of 86 (11.6%) sera and 3 of 14 (21.4%) ascites from hepatocellular carcinoma patients showed positive bindings, whereas only 1 of 35 (2.8%) sera, none of 4 (0%) ascites from chronic hepatitis patients and 3 of 60 (5%) normal human sera had positive immunofluorescent antibody activity. The binding specificities of these positive specimens were further defined by other human cancer cell lines and mouse NIH/3T3 fibroblasts. The antinuclear antibody test against mouse liver sections was also performed. The results suggested that antigens identified by the two tests may not be identical. The nature of nuclear antigens reactive with one of the serum samples, S83, and ascites A83 were characterized. These antigens were sensitive to trypsin but not to RNase A and DNase I. Further studies by radioimmunoprecipitation and two-dimensional gel electrophoresis with serum S83 and ascites A83 showed two acidic phosphorylated antigens with molecular weights of 77 and 79 kd, which had a pI around pH 5.2. The presence of a large amount of these two phosphorylated proteins in 5 of 7 human hepatocellular carcinoma cell lines suggests that these two antigens might play some roles in the carcinogenesis or progression of human hepatocellular carcinoma.

Differential response of the human hepatoma-derived cell line HA22T/VGH to polypeptide mitogens

Several human cell lines derived from primary cancer of the liver are able to grow under serum-free conditions and produce spreading and growth factors which are released into the culture medium. Since this autocrine growth under hormone-free conditions might play a basic role in malignant transformation, we studied the effect on cell replication and the presence of specific membrane receptors of epidermal growth factor (EGF) and insulin on a dedifferentiated human hepatoma cell line, named HA22T/VGH. Our results point to a similar inhibitory effect on cell replication in the presence of both EGF and insulin, in spite of detecting different affinities of binding.

Karyotypic characterization of an established human hepatoma cell line HA22T/VGH

The karyotype of an established human hepatoma cell line HA22T/VGH was characterized by G-banding. A majority of the 200 cells counted had around 70 chromosomes at passage 24, and 60 at passage 338. Of the 50 cells karyotyped from each of passage 24 and passages 338-339, chromosomes #13 and #18 were absent. The presence of the Y chromosome was reduced dramatically from a mean value of 1.12/cell at passage 24 to 0.12/cell at passages 338-339. In general, most of the chromosomes--particularly chromosomes #5, #7, #9, #15, and #21--tended to be less represented in the course of propagation in vitro. The presence of multiple copies of a normal chromosome in a single cell was quite common for chromosomes #5 and #7 at both early and late passages. Numerous structural rearrangements of the chromosomes were observed.

Absence of cytokeratin in human hepatoma cell lines

The immunofluorescence study revealed that both our established human hepatoma cell lines, HA22T/VGH and HA47T/VGH, were absent of cytokeratin. This observation was further confirmed by a western blot study. However, they as well as the other human hepatoma cells, Hep G2, Hep 3B, and SK-Hep-1 expressed vimentin.

Investigations on the role of Golgi-mediated, ligand-receptor processing in the activation of granulocytes by chemoattractants: differential effects of monensin

Human granulocytes were exposed to different concentrations of the ionophore monensin for 20 min at 37 degrees C. Subsequent exposure to 50 nM of the chemoattractant fMet-Leu-[3H]Phe for up to 30 min at 37 degrees C resulted in a receptor-mediated uptake that was inhibited 80% at a monensin concentration of 30 microM. 50% inhibition was observed at 1-10 microM monensin with no significant change in fMet-Leu-Phe dose dependency. Subcellular fractionation of cells treated with monensin, indicated that the low density UDP-galactosyltransferase activity associated with internalized receptor-fMet-Leu-Phe complexes in untreated cells was absent. The high density galactosyltransferase activity cosedimenting with specific granule markers, however, was unaffected. Monensin also inhibited chemotaxis toward fMet-Leu-Phe as measured by migration of granulocytes through millipore filters and fMet-Leu-Phe induction of polarized morphology. Incubation of cell suspensions with up to 30 microM monensin, both before and during measurement of fMet-Leu-Phe stimulated superoxide production, did not affect the magnitude, kinetics, or transiency of the radical generation. Monensin did, however, shift the dose dependency of superoxide production of fMet-Leu-Phe to higher concentrations. These differential effects of monensin suggest that endocytosis of complexes of the chemoattractant and receptor is not involved in the activation or termination of the fMet-Leu-Phe stimulated superoxide production. They also are consistent with a role for receptor modulation and processing in the chemotactic response.

Antibody for detection and quantitation of membrane-associated folate-binding protein from Lactobacillus casei

Lactobacillus casei cells contain a 25 kDa, membrane-associated, folate-binding protein (fbp), which is a component of the folate transport system. Polyclonal antibody to fbp (anti-fbp) has been prepared, and conditions have been established for detection and quantitation of the protein. Anti-fbp did not block [3H]folate transport or binding in L. casei cells. As judged by Western blots, the antibody reacted only with fbp on sodium dodecyl sulfate electrophoretograms of Triton X-100 extracts of L. casei membranes. Anti-fbp showed no cross-reactivity with L. casei dihydrofolate reductase, L. casei 5,10-methenyltetrahydrofolate synthetase, L1210 dihydrofolate reductase, rat liver dihydrofolate reductase, or L1210 folate-binding protein. Enzyme-linked immunosorbent assay measurements indicated the presence of an fbp in membranes of Lactobacillus salivarius and two transport-defective sublines of L. casei. Anti-fbp was used to demonstrate selective extraction, with n-butanol, of fbp from a mixture of Triton-solubilized L. casei membrane proteins; repression of fbp in membranes of L. casei cells grown on high levels of folate; and localization of fbp by electron microscopy, using anti-fbp in conjunction with goat anti-rabbit IgG gold conjugate, in L. casei membranes.

Production of hepatitis B virus in vitro by transient expression of cloned HBV DNA in a hepatoma cell line

Transfection of human hepatoma cell lines with cloned HBV DNA resulted in the secretion of large amounts of hepatitis B surface antigen (HBsAg) and core-related antigens (HBc/HBeAg) if well-differentiated cell lines were employed. Synthesis of both viral antigens was the highest in cell line HuH-7 and continued for approximately 25 days. Particles resembling hepatitis B virions (Dane particles) by morphology, density and by the presence of the preS1 surface antigen were released from the transfected HuH-7 cells into the culture medium. These particles produced in vitro were also indistinguishable from the naturally occurring hepatitis B virions in containing the virus-associated DNA polymerase and mature HBV genomes. Restriction analysis of these DNA molecules was compatible with the nucleotide sequence of the transfecting HBV DNA sequence. Viral surface antigens and core proteins present in the culture medium were fractionated and characterized by immunoprecipitation and SDS--PAGE after labeling with [35S]methionine. Antisera specific for X-gene products identified in cell extracts two hitherto unknown HBV gene products. This system thus provides a new approach to open questions regarding HBV-related gene function and HBV replication.

Herpes zoster and its neurological complications

Ninety-three Chinese patients with cutaneous herpes zoster were seen during a 4-year period. Thoracic zoster occurred most commonly, followed by ophthalmic, cervical and lumbosacral zoster. Neurological complications were present in eleven patients (11.8%), the commonest being Ramsay-Hunt syndrome and segmental limb paresis. The clinical picture, pathogenesis, treatment and outcome of segmental limb paresis, myelitis and delayed contralateral hemiparesis following zoster ophthalmicus are discussed. Nine immunocompromised patients received intravenous adenine arabinoside (vidarabine) or acycloguanosine (acyclovir), and no cutaneous or visceral spread occurred in these patients.

Selective suppression of insulin-induced proliferation of cultured human hepatoma cells by somatostatin

The effects of somatostatin (SRIF), insulin, and triiodothyronine (T3) on the growth of human hepatoma cells were investigated on the well-differentiated human hepatoma cell line Hep3B. Results showed that both insulin and T3 can stimulate cell growth of serum starved Hep3B cells at physiological concentrations. SRIF alone showed little growth-promoting activity. When added concurrently with insulin, however, SRIF suppressed the insulin-induced cell proliferation in a dose-dependent manner. On the other hand, SRIF had no inhibitory effect on T3-induced cell proliferation. SRIF is labile in the medium, with a half-life of about 2 h during culture incubation. SRIF did not disturb the insulin binding to its surface receptors nor inhibit the insulin-dependent receptor kinase activity of Hep3B cells in vitro. These results suggest that postreceptor regulation may be involved. The selective suppression by SRIF of insulin-induced cell growth provides an unique approach to the study of insulin actions on proliferation of human hepatoma cells.

Tuberculous meningitis associated with meningeal tuberculoma

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Hepatitis B virus transcripts in a human hepatoma cell line, Hep 3B

Hep 3B, a human hepatoma cell line was examined for its RNA hybridizable to the hepatitis B virus sequence. Using probes that covered different regions of the hepatitis B virus genome, five species of RNA were observed of sizes 4.0, 3.3, 2.9, 2.6 and 2.2 kilobases. The RNAs covered surface antigen gene, pre-S and X regions. None of them had a core antigen sequence. RNA with a 4.0 kilobase size was the most abundant. Using S1 nuclease analysis, its 5' end of hepatitis B virus sequence was mapped at pre-S region and its 3' end of viral sequence was mapped at DR region.

Detection of circulating immune complexes in liver diseases, systemic lupus erythematosus and glomerulonephritis by polyethylene glycol precipitation

A method for detection and quantitation of circulating immune complexes using precipitation of the complexes by polyethylene glycol (PEG) has been reexamined to determine the influence of pH on the recovery and the reproducibility of the results. Results showed that the pH optimum for these determinations was 7.8. The recovery percentages range from 57.8-146.5% at lower immune complex concentrations, and from 73.9-101.3% at higher concentrations. The reproducibility of the method seems reasonably acceptable with a percent coefficient of variation ranging from 0.5-9.5. This method for quantitation of circulating immune complexes by polyethylene glycol precipitation is consistent and relatively reliable. Using this method, the levels of circulating immune complexes in sera in patients with hepatitis, liver cirrhosis, hepatoma, acute post-streptococcal glomerulonephritis (before and after treatment) and systemic lupus erythematosus have been examined. The results showed that except the patients with treated acute post-streptococcal glomerulonephritis who had a similar amount of immune complexes with normal controls, the level of immune complexes in patients with other types of diseases were all higher than the control. In addition, the composition of IgG, IgA, IgM, C3 and C4 of the precipitable complexes in sera of patients with three types of liver disease has been analyzed and demonstrated that the percentages of IgM were higher than the normal control. However, C3 and C4 in hepatitis and liver cirrhosis patients were lower than those of the control.

Interaction between carbamazepine and dextropropoxyphene

Serious side effects may result from the concurrent administration of the usual dosage of carbamazepine and dextropropoxyphene. Three cases are reported and the mechanisms and implications discussed.

Chromosome analysis on a cell line (CE48T/VGH) derived from a human esophageal carcinoma

The cell line CE48T/VGH was established from an epidermoid carcinoma of the middle third of the esophagus of a 58-year-old male patient. Cytogenetic analysis at passages 90-99 showed that the line was hypotetraploid, with a mean chromosome number of 73. None of the 50 karyotyped cells had a normal chromosome #1 or Y. Cells with multiple copies of some of the autosomes were observed frequently. Structural rearrangements were numerous, especially of chromosomes #1, #9, #14, X, and Y.

Circulating immune complexes in the sera and ascites of hepatocellular carcinoma or chronic hepatitis patients

Circulating immune complexes (CIC) in the sera or ascites of hepatocellular carcinoma (HCC), chronic hepatitis patients and normal healthy persons were measured by polyethylene glycol (PEG) and C1q solid-phase microassay (C1q-SPMA). Both the PEG and C1q-SPMA methods showed the serum CIC levels of HCC patients were significantly higher than those of chronic hepatitis patients and of normal persons. The CIC levels of chronic hepatitis patients were also significantly higher than those of normal persons as detected by PEG method but not by C1q-SPMA. The ascites from HCC patients also had CIC. But the amount of CIC in ascites was significantly lower than those of the serum from the same HCC patients. These results suggest that the increase of CIC may play some pathological role in the HCC patients.

Cytomegalovirus viremia increases with progressive immune deficiency in patients infected with HTLV-III

Cytomegalovirus (CMV) viremia was studied in 15 homosexual patients [two healthy, nine with the acquired immune deficiency syndrome (AIDS), five with the AIDS-related complex (ARC)], in one patient with transfusion-related AIDS, and in four individuals with cancer or connective tissue disorders. While CMV viremia was absent in the latter patients, in the healthy homosexuals, and in three stable ARC patients, it was present in clinically-deteriorating ARC patients and in all nine AIDS patients. Some CMV isolates caused limited proliferation of fibroblasts in the culture medium. The rapidity and ease of CMV isolation from leukocytes of patients at different stages of infection with human T-lymphocytotropic virus type III (HTLV-III) indicate that the CMV titer in leukocytes increases as immune deficiency worsens. In ARC patients CMV viremia may be predictive of clinical complications in the next 3 months. In AIDS patients CMV viremia at high titer was an unfavorable prognostic sign.

Expression of c-myc gene in human hepatoma

The level of c-myc transcript was examined in liver samples from seven hepatoma patients. Transcripts were detected in all the normal liver parts examined; in contrast, in two hepatoma parts, there was a dramatic reduction in c-myc transcripts. The restriction enzyme pattern of c-myc gene appeared the same among samples. The data suggest that c-myc gene expression might not be required for the maintenance of the tumor state in human liver carcinogenesis.

Pancreatic islets contain the M2 isoenzyme of pyruvate kinase. Its phosphorylation has no effect on enzyme activity

To determine which of the major isoenzymes of pyruvate kinase pancreatic islet pyruvate kinase most resembled, it was compared to pyruvate kinase from other tissues in kinetic and immunologic studies. The pattern of activation by fructose bisphosphate and the patterns of inhibition by alanine and phenylalanine were most similar to those of the M2 isoenzyme from kidney and were dissimilar to those of the isoenzymes from skeletal muscle (type M1) and liver (type L). The islet pyruvate kinase was inhibited by anti-M1 pyruvate kinase serum (which crossreacts with the M2 isoenzyme), but not by anti-L pyruvate kinase. These results are most consistent with islets possessing predominantly, if not exclusively, the M2 isoenzyme of pyruvate kinase. We previously showed that rat pancreatic islet cytosol contains protein kinases that can catalyze a calcium-activated phosphorylation of an endogenous peptide that has properties, such as subunit molecular weight and isoelectric pH, that are identical to those of the M2 and M1 isoenzymes of pyruvate kinase, and that islet cytosol can catalyze phosphorylation of muscle pyruvate kinase. In the present study it was shown that incubating islet cytosol with ATP under conditions known to permit phosphorylation and inhibition of liver pyruvate kinase did not affect the islet pyruvate kinase activity. It is concluded that phosphorylation of the islet pyruvate kinase has no immediate effect on enzyme activity.

Evidence for phosphorylation of pancreatic islet pyruvate kinase

Rabbit pancreatic islet cytosol catalyzes the calcium-activated phosphorylation by [gamma 32P]ATP of a protein with a molecular weight of 57,000 that is precipitated with antipyruvate kinase antibodies. We were unable to demonstrate that phosphorylation in the presence of calcium or cAMP had any immediate effect on rat pancreatic islet pyruvate kinase activity. This finding is consistent with our inability to confirm the finding of others that pancreatic islets contain phosphoenolpyruvate carboxykinase activity (Diabetes, 34:246, 1985). Since the carboxykinase catalyzes phosphoenolpyruvate formation and pyruvate kinase catalyzes essentially the opposite reaction, if the carboxykinase were present in the beta cell, pyruvate kinase would need to be inhibited to prevent recycling of phosphoenolpyruvate.

Activation of pancreatic islet myosin ATPase by ATP and actin

Previous work from our laboratory indicated that pancreatic islets contain myosin light chain kinase, a calcium- and calmodulin-activated enzyme. This enzyme catalyzes phosphorylation of myosin which, in tissues containing smooth muscle, is believed to permit the ATPase of myosin to be activated by actin. The current report shows that incubating islet cytosol with ATP under conditions that should permit phosphorylation of myosin markedly enhances islet myosin ATPase activity in the presence of actin. It has been suggested that contractile proteins power insulin granule movements in the beta cell. Phosphorylation of myosin may be one of the means of coupling stimuli to insulin secretion.

Cellular and antigenic properties of cultured normal and fetal brain and glioma cells

The immunological and cellular properties of cultured normal and fetal brain cells as well as glioma cells were compared. They were grown successfully in tissue culture media. Results from the growth properties and karyotype analysis indicated that cultured cells from normal and fetal brain tissues were normal and could be passaged limited times. The fetal brain cells had a longer life span than normal brain cells in the culture and their morphology exhibited variations according to cell passages. Two glioma cell lines, designated as G-5-T and G-9-T were established. The G-5-T and G-9-T had different morphology. Both G-5-T and G-9-T formed colonies in the soft agar. However, only G-9-T cells grew as large tumors in nude mice. Neither cell line secreted CEA, AFP and did not contain GFAP and S-100 protein. As measured by the 51Cr cytotoxicity assay, G-9-T but not G-5-T cells possessed D/DR antigens.

Characterization of cell surface adenosine 3',5'-monophosphate-binding proteins in Y-1 mouse adrenal tumor cells

Adrenal cortical cells are known to export cAMP and have binding proteins and cAMP-dependent protein kinase activity associated with their plasma membranes. Because these properties suggest a function for extracellular cAMP, we have undertaken a search for specific cell surface receptors for this cyclic nucleotide. Y-1 mouse adrenal tumor cells actively export cAMP by an energy-dependent process. Analysis of Scatchard plots of the equilibrium binding of [3H]cAMP to these cells indicate the existence of two classes of cAMP binders: one with high affinity (ka = 2.9 X 10(9) M-1) and another with low affinity (ka = 7.0 X 10(7) M-1). The cell surface localization of these binders was established by the sensitivity of both the [3H]cAMP-binding proteins and the [32P]8-N3-cAMP photoaffinity labeled proteins of intact cells to mild trypsin digestion and by the surface distribution of a BSA-O2-monosuccinyl cAMP-gold complex revealed by electron microscopy. Analysis of radioautograms of cell surface cAMP-binding proteins from confluent monolayer tumor cells, photoaffinity labeled with [32P]8-N3-cAMP and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two major 32P-labeled protein bands which were indistinguishable from the 49,000 and 55,000 mol wt regulatory subunits of the cytosolic protein kinase isoenzymes of this cell. These observations along with the demonstration of cell surface, cAMP-dependent protein kinase activity in the mouse adrenal tumor cell strongly suggest that these cAMP-binding proteins function as regulatory proteins for cell surface protein kinases.

Do pancreatic islets contain significant amounts of phosphoenolpyruvate carboxykinase or ferroactivator activity?

Phosphoenolpyruvate carboxykinase activity was measured in rat pancreatic islet cytosol and mitochondria. No carboxykinase activity was detected under a variety of conditions, including those that increase phosphoenolpyruvate carboxykinase activity in nonislet tissues, such as starving animals or incubating the islet extracts with Fe2+ or Mn2+ before assaying for enzyme activity. The amounts of islet cytosol protein used exceeded those of liver in companion assays used as controls. It was calculated that if islet phosphoenolpyruvate carboxykinase activity was 0.005 that of liver, or 1 X 10(-5) as high as pyruvate kinase activity in islets, it should have been detected in the assays used. Ferroactivator is a protein that permits Fe2+ to activate phosphoenolpyruvate carboxykinase and it is ubiquitous to many tissues that do and even do not contain the carboxykinase. Ferroactivator activity was not detectable in pancreatic islets. Pyruvate kinase, an enzyme that catalyzes a reaction that is essentially the opposite of that catalyzed by phosphoenolpyruvate carboxykinase (i.e., phosphoenolpyruvate formation), is plentiful in islet cytosol. Therefore, even if phosphoenolpyruvate carboxykinase activity is present in pancreatic islets, it is so low that it is unlikely that phosphoenolpyruvate formation would be favored and the contribution of the carboxykinase to intracellular carbohydrate metabolism must be quantitatively unimportant.

Endogenous opioid peptides in intrapartum uterine blood

Endogenous opioid peptides have consistently been reported to exert significant influence on several parameters of reproductive physiology, including tolerance to pain, release of prolactin, pleasurable behavior patterns, and appetite satiety. Immunoreactive endorphins measured in several hundred samples of postpartum uterine blood had a mean value of 190 pg/ml and a range of 60 to 520 pg/ml. Individual values in 100 mothers who were delivered at the Northwest Hospital failed to correlate with doses of postpartum pain medications, infant feeding patterns, and recorded estimates of maternal bonding behavior. Postpartum "blues" may be related to stress-induced depletion of endorphinergic systems.

Biologic properties of three newly established human esophageal carcinoma cell lines

Three epithelial cell lines, CE-48T/VGH, CE-69T/-VGH, and CE-81T/VGH, were established from human squamous cell carcinoma of the esophagus. The cells were polygonal with a high nucleus-to-cytoplasm ratio. Many cells were multinucleate. Electron microscopy revealed the presence of tonofilaments and desmosomes. Chromosome analysis showed that these 3 cell lines were heteroploids of human origin. When transplanted into BALB/c (nu/nu) mice, CE-69T/VGH and CE-81T/VGH produced tumors, the histology of which proved to be carcinomas. All 3 cell lines secreted carcinoembryonic antigen. However, the secretion patterns were different. These 3 cell lines may provide useful models for the study of human esophageal cancer.

Circulating immune complexes in cervical cancer patients as detected by C1q binding

In a retrospective study in women with cervical cancer, circulating immune complex levels were measured by radioimmunoprecipitation with 125I-C1q. Sera from 46 patients with cervical cancer and 35 normal controls were examined. Significantly higher levels of immune complexes were detected in cancer patients compared with controls. Mean value of binding capacity in patients was 49.8%, and by contrast, in the controls was 27.4% (two-tail test = 0). Increases in tumor mass were associated with high levels of circulating immune complexes. The presence of immune complexes in circulation statistically correlated with disease activity, however, the assay used still had limited value for diagnosis or aiding in therapeutic decisions. Nevertheless, the future holds promise for such uses.

Complement-mediated binding of monocytes to intermediate filaments in vitro

An in vitro model for complement (C)-mediated monocyte binding to injured cells is described. This model is based on the property of cytoskeletal intermediate filaments (IMF) to directly and independently activate serum C via the classic pathway. Fixed monolayers of cultured fibroblasts, endothelial cells, and L 132 epithelial cells were each used as targets. The authors first subjected the target cells to limited detergent extraction in order to make permeable the plasma membrane, and then exposed them to normal human serum. Immunohistologic analysis demonstrated that this process permitted binding of clearly demonstrable amounts of C1q, C4, and C3 to cytoplasmic loci containing IMF. The target cells were then incubated for various lengths of time with peripheral blood mononuclear cells containing about 20% monocytes. Preferential binding of monocytes was demonstrated by histochemical and immunologic staining methods. Only 5% of the attached cells were B lymphocytes. By transmission electron microscopy the attached cells exhibited typical monocyte morphology. Attachment to target cells involved contact with areas rich in IMFs and led to signs of activation; both an increased number of cytoplasmic organelles and phagocytosis of target cell material were observed. Attachment of monocytes was clearly dependent on serum treatment of the targets; the ratio was 10:1 when compared with control experiments using target cells that had not been incubated with serum. It is reasonable to consider that bound monocyte-derived macrophages associate with activated C components, most likely C3b fragments or C1q, for which monocyte surface receptors have been established. This mechanism may be triggered in various inflammatory reactions involving cell and tissue injury and as an event in the final stages of macrophage-mediated removal of injured or nonviable cells.

[A new human hepatoma cell line: establishment and characterization]

We have grown a human hepatoma cell line, designated as HA22T/VGH, from a 52-yr-old male hepatoma patient since July 1, 1980. This cell line has been subcultured more than 100 passages. The chromosome analysis of HA22T/VGH indicated that the chromosome numbers varied from 70 to 146, with the mode of 73. Methylcellulose soft agar assay showed that approximately 40% of the HA22T/VGH cells formed colonies. The HA22T/VGH produced tumors in nude mice. Histopathological studies of the tumor revealed the arrangement of hepatoma. Detected by the complement fixation method HA22T/VGH cells secreted ceruloplasmin, Factor B, C3, C4, Gc-globulin and alpha 1-acid-glycoprotein. These cells contained the liver associated enzymes: alanine amino transferase, tyrosine amino transferase and gamma-glutamyl transferase. HBsAg and alpha-fetoprotein were not detectable in the HA22T/VGH culture media or cell lysates by the radioimmunoassay.

Immunoreactive endorphin peptides and prolactin in umbilical vein and maternal blood

Immunoreactive endorphin peptides (ir EP) and prolactin (PRL) were measured by radioimmunoassay in venous blood from the umbilical cord of 86 neonates, 23 postpartum mothers, and 40 randomly selected blood bank donor control subjects. We also assayed these hormones in serosanguineous placental tissue fluid following delivery. The data suggest both ir EP and PRL are elevated during both processes and that placental chemistry may be implicated in blood levels of these hormones. Some biological and clinical aspects of placental opiates are discussed.