[The biological behaviors of inoculated B16 melanoma in mice: correlation with NK activity of the host]

B16 melanoma cells with different natural killer (NK) cell activity were inoculated subcutaneously in mice. Observations were made on the relation of NK cell activity to tumor growth, infiltration and metastasis on the one hand and, the sensitivity of the tumor cells to NK cells before and after tumor implantation on the other. It was seen that NK cells could not only inhibit tumor growth, infiltration and metastasis, but also induce tumor NK-tolerance of the tumor. When the NK-tolerant tumors were resected and implanted into ordinary mice, the biological behaviors of NK-tolerant B16 tumor cells were more malignant than wild (original) B16 cells. The results of this study show that the in vivo interaction between NK cells and tumor cells can positively and negatively influence the tumor's biological behaviors.

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Serum cholesterol determined by liquid chromatography with 6-chlorostigmasterol as internal standard

We describe an accurate and precise method for determining serum cholesterol by high-performance liquid chromatography (HPLC). After addition of 6-chlorostigmasterol as internal standard, serum is treated with alcoholic potassium hydroxide. Subsequently the cholesterol and internal standard are extracted from the mixture into n-hexane and then derivatized to phenylurethanes for measurement by HPLC with ultraviolet detection. The effective chromatographic separation and the use of an appropriate internal standard make this procedure free from interferences by other serum sterols and precise. The mean cholesterol concentration in Standard Reference Material (SRM) 909 (human serum) assayed by this procedure (4.346 mmol.g-1 x L-1) agreed well with the value assigned by the National Institute of Standards and Technology (4.359 mmol.g-1 x L-1). Within-run and total CVs were 0.56% and 0.78%, respectively. Therefore the performance of this procedure is sufficiently good to allow its use as a candidate reference method for serum cholesterol determination.

Taxonomic and population differentiation of mitochondrial diversity inPinus banksiana andPinus conforta

We have studied two mitochondrial DNA polymorphisms in 741 individuals from 16 allopatric populations ofPinus banksiana Lamb. andPinus contorta Dougl. Restriction fragments of both polymorphisms distinguished the two species qualitatively, except in aP. Banksiana population whose ancestors were involved in hybridization withP. contorta.COXI-associated restriction fragments were monomorphic within species, whileCOXII-associated restriction fragments were highly variable inP. contorta (Hes=0.68). Population differentiation was substantial inP. contorta (Fst=0.31 among subspecies; mean Fst=0.66 within subspecies) and consistent with predictions for maternally inherited markers. Plant mitochondrial markers appear to be useful for the investigation of seed migration routes, hybridization and introgression, breeding zone designation, and the development of germ plasm conservation sampling strategies.

Analysis of retroviral assembly using a vaccinia/T7-polymerase complementation system

The nature of protein-protein interactions during retroviral assembly is not well understood, and mutational analyses of the potential signals involved in the viral assembly process has been difficult, particularly with the avian retroviruses due to the level of viral proteins expressed in the clonal cell lines containing defective viral genomes. We describe here a complementation system in which the retroviral gag/pol and env gene products were expressed independently from different plasmids under the control of the bacteriophage T7 promoter, in avian cells. Coexpression of the T7 polymerase from a vaccinia virus vector resulted in a high level of biosynthesis of retroviral structural proteins and efficient assembly of virus particles. Electron microscopy and protein composition analyses demonstrated that these virions were indistinguishable from those produced from RSV-infected cells. Through the use of mutant glycoprotein genes it was possible to demonstrate the specificity of the assembly process and the applicability of this system to other retroviral systems is described.

A chimeric avian retrovirus containing the influenza virus hemagglutinin gene has an expanded host range

We have investigated what protein sequences are necessary for glycoprotein incorporation into Rous sarcoma virus (RSV) virions by utilizing the hemagglutinin (HA) protein of influenza virus. Two chimeric HA genes were constructed. In the first the coding sequence for the signal peptide of the RSV env gene product was fused in frame to the entire HA structural gene, and in the second the hydrophobic anchor and cytoplasmic domain sequences of the HA gene were also replaced with those from the RSV env gene. Both chimeric genes, expressed from a simian virus 40 expression vector in CV-1 cells, yielded functional HA proteins that were transported to the cell surface and were able to bind to erythrocytes. When the genes were expressed in combination with the RSV gag-pol gene region in QT6 cells by using a vaccinia virus-T7 expression/complementation system, virions that efficiently incorporated either chimeric protein were assembled. This result indicated that the presence of the RSV env membrane anchor and cytoplasmic sequences did not facilitate HA glycoprotein incorporation into virions. The presence of the RSV env signal sequence allowed the chimeric HA genes to be substituted into the RSV-derived BH-RCAN.HiSV viral genome in place of the RSV env gene. Both chimeric genomes yielded infectious virus that could infect human and avian cells with equal efficiency. These experiments demonstrate that a foreign glycoprotein, efficiently incorporated into virions lacking a native glycoprotein, can confer a broadened host range on the virus. Moreover, because the HA of influenza virus requires the acidic pH of the endosome in order to be activated, these results imply that foreign proteins can modify the normal route of entry of this avian retrovirus.

Localization of metastasis suppressor gene(s) for prostatic cancer to the short arm of human chromosome 11

Previous studies using somatic cell hybridization of highly metastatic and nonmetastatic rat prostatic cancer cells demonstrated that the resultant hybrids were nonmetastatic if all of the parental chromosomes were retained. Somatic hybrid segregants which underwent nonrandom chromosomal losses reexpressed high metastatic ability. These results demonstrated that there are gene(s) the expression of which can suppress metastatic ability of prostatic cancer cells. To identify the location of homologous gene(s) in the human, specific human chromosomes were introduced into highly metastatic rat prostatic cancer cells using the microcell-mediated chromosome transfer. Introduction of human chromosome 11 into highly metastatic rat prostate cancer cells results in suppression of metastatic ability without suppression of the in vivo growth rate or tumorigenicity of the hybrid cells. Spontaneous deletion of portions of human chromosome 11 in some of the clones delineated the minimal portion of human chromosome 11 capable of suppressing prostatic cancer metastases as the region between 11p11.2-13 but not including the Wilms' tumor-1 locus.

Simultaneous identification of estrogen and progesterone receptors by HPLC using a double isotope assay

Polymorphism of estrogen (ER) and progestin receptors (PR) was analyzed simultaneously using high performance hydrophobic interaction chromatography (HPHIC). HPHIC was used previously to characterize four ER isoforms [Hyder et al., J. Chromat. 397 (1987) 251] based on retention times on Synchropak propyl (100 x 6 mm) HPLC columns (Synchrom, Inc.). ER and PR were prepared from human breast cancer. ER was labeled with 3 nM of either [3H]estradiol-17 beta ([3H]E) or [125I]iodoestradiol-17 beta ([125I]E) while PR was associated with 5 nM of either [3H]R5020 ([3H]R) or [125I]iodovinylnortestosterone ([125I]V). ER was resolved by HPHIC into isoforms MI (Rt = 11 min), I(Rt = 16 min), and II (Rt = 24 min). Isoforms I and II each accounted for ca 45% of specific binding. PR separated into isoforms MI (Rt = 14 min) and I (Rt = 21 min, 80% of specific binding) when eluted with the same gradient used for ER chromatography. Upon inclusion of 10 mM molybdate ER resolved into isoforms MI and MII (Rt = 16 min) and PR into isoforms MI and I (here however isoform MI represented 80-95% of specific binding). Elution patterns were preserved with different batches of stationary phase suggesting the integrity of the isoform distribution. HPLC profiles of ER isoforms labeled with earlier [125I]E or [3H]E were identical as were PR isoform profiles labeled with either [3H]R or [125I]V. Pairs of 125I- and 3H-labeled ligands were used in either combination to monitor ER and PR profiles simultaneously. Isoforms analyzed in 50 biopsies gave reproducible retention times, however the ratio between I and II for ER and MI and I for PR varied. This method allows rapid, simultaneous monitoring of the chromatographic behavior of ER and PR isoforms or other associating proteins or nucleotides. One may now better elucidate their interrelationship as it relates to the hormone-response mechanism.

[Effect of radix Astragali and radix ginseng in enhancing the metabolism of human myocardial cells in vitro]

Our experiment indicated that in Radix Astragali and Radix Ginseng treated human myocardial cell cultures the level of LDH and SDH elevated in varying degrees and in Radix Ginseng treated cells the cAMP showed higher levels but in Radix Ginseng treated ones the same was not observed. This suggests that the metabolism of myocardial cells is enhanced by Radix Astragali or Radix Ginseng.

Islet cell and extrapancreatic expression of the LIM domain homeobox gene isl-1

The phenotypically distinct cell types of the islets of Langerhans express a number of different hormone genes in a regulated and cell-specific manner. Analysis of the molecular factors important for the control of insulin gene transcription has led to the identification of a number of insulin gene-binding proteins. The cDNAs for several of these proteins have been isolated, including isl-1, a LIM domain homeobox protein reported to be preferentially expressed in islet cells. We now report that isl-1 mRNA transcripts are present not only in islet cells, but also in pheochromocytoma (PC-12) cell lines. Isl-1 mRNA transcripts were also detected in several different regions of rat brain as well as in rat kidney. Analysis of the patterns of gene expression in rat islet cell lines and human pancreatic endocrine tumors demonstrated a variable relationship between the hormonal phenotype of the tumor and expression of the isl-1 and insulin genes. Immunocytochemical studies demonstrated both cytoplasmic and nuclear staining for isl-1 in human pancreatic endocrine tumors, in normal pancreatic A, B, D, and PP cells, and in distal tubular cells of the kidney. Isl-1 immunoreactivity was also widely distributed in neurons in both the central and peripheral nervous system, pituitary, and several human pituitary tumors and pheochromocytomas. The results of these studies implicate a potential role for isl-1 outside the endocrine pancreas in the nervous system and kidney.

Paternal leakage of mitochondrial DNA inPinus

We studied mitochondrial DNA restriction fragment length polymorphism in 11 parents and 125 seedlings of 23 controlled matings within and between jack pine (Pinus banksiana Lamb.) and lodgepole pine (P. contorta Dougl.). A potential mitochondrial distinction between these two conifers was evident in the parental samples. Only maternal mitochondrial restriction fragments were observed in a majority of the seedlings, which is consistent with results from angiosperms and other members of the genusPinus L. However, we detected exclusively paternal mitochondrial DNA in six of the seedlings. These unusual seedlings were not attributable to heteroplasmy or contamination of the experimental material, indicating that mitochondrial inheritance was not strictly maternal. Paternal mitochondrial leakage inPinus may permit novel insights into the transmission genetics and evolution of organellar polymorphisms.

Development and characterization of polyclonal antibodies against chicken adipocytes

1. Antisera against chicken adipocytes were developed in sheep. These crude antisera showed a high degree of reactivity to adipocyte plasma membranes but also cross-reacted to a lesser extent with other tissues. 2. Antisera cross-reactivity was removed by adsorption of the antisera with various chicken tissue plasma membranes. 3. Antisera reacted with differing affinity to adipocyte plasma membranes from several species of animals.

Expression and characterization of an active human estrogen receptor as a ubiquitin fusion protein from Escherichia coli

The gene coding for the human estrogen receptor protein was expressed as a ubiquitin fusion under the control of the lambda PL promoter in Escherichia coli. Analysis of extracts by Western blot showed that intact receptor protein was produced only when PL promoter was depressed by nalidixic acid at 30 degrees C. To ascertain the intactness of the expressed protein, estrogen receptor in bacterial extracts was titrated with either 17 beta-[3H]estradiol or 17 beta-[125I]iodoestradiol, and the mass was quantified by enzyme immunoassay. Cell extracts contained 484 fmol of estrogen receptor per mg of soluble protein by titration with a Kd of 3.2 x 10(-10) M. The simultaneous analysis by enzyme immunoassay resulted in 487 fmol/mg of extract protein indicating that most of the expressed protein bound ligand with wild type properties. Ligand competition analysis demonstrated that expressed receptor contained a binding domain preferentially recognizing estrogenic substances identical with that of wild-type estrogen receptor. The E. coli-expressed estrogen receptor also associated specifically with estrogen response DNA elements. Full length receptor protein was detected by ligand binding and immunorecognition using size exclusion chromatography. Hydrophobic interaction chromatography showed a major isoform which exhibited both ligand binding and immuno-recognition identical with the estrogen receptor from human breast tumor tissues. These data indicate that estrogen receptor expressed in E. coli retained characteristics of the native protein found in human tissues.

[Effects of As2O3, MNNG and B(a)P on epithelia of human fetal tracheae and rat tracheae in organ culture]

The effects of As2O3, MNNG and B(a)P on epithelia of human fetal tracheae and rat tracheae in organ culture were studied. In human fetal trachea, a small dose of arsenic (1 mumol As) induced hyperplasia of the epithelium; 3-9 mumol As induced hyperplasia and cellular atypia in the epithelium, and hyperplasia and squamous metaplasia in the adenoepithelium. Similar effects were not observed in rat tracheae. MNNG and B(a)P induced hyperplasia, squamous metaplasia and dysplasia in human fetal tracheal and rat tracheal epithelia respectively, and MNNG also induced hyperplasia and squamous metaplasia in human fetal tracheal adenoepithelium. The data suggest that 1) arsenic may be carcinogenic to the human respiratory tract but not to the rat; and 2) human tissues in organ culture are very useful for detecting carcinogens and for studying carcinogenesis.

[Cytolytic action of normal human natural killer cells on CNE-2 nasopharyngeal carcinoma cell in vitro]

Cytolytic actions of human natural killer cells, which were separated with nylon wool column from normal human peripheral blood, were investigated on human nasopharyngeal carcinoma cell line cells (CNE-2) and the dynamic processes of conjugation and cytolysis were studied. It was found that NK cells attacked living target cells and the course of cytolysis might be divided into 2 types according to their rapid or slow responses. In addition to the large granular lymphocytes the non-granular lymphocytes also participated in NK functions.

[Cyclic AMP levels in the plasma and ischemic myocardium and free fatty-acid levels in the serum following coronary artery ligation in dogs: relation to ventricular fibrillation]

This study was designed to shed light on the biochemical causes of serious ventricular arrhythmias in the early stage of acute myocardial infarction (AMI). Fourteen mongrel dogs were divided into 2 groups. One group was subjected to coronary ligation by placing silk sutures around the LAD coronary artery about 1.5 cm from its origin. All the dogs of this group were found to have ventricular tachycardia and fibrillation, starting approximately 18 min. After ligation, associated with regional accumulation of myocardial cAMP in the ischaemic zone. The increase of cAMP started about 10-15 min. before the onset of the arrhythmia. In contrast, the control group had only sutures placed without ligation and was not found to have change in myocardial cAMP within 35 min and arrhythmias at the same time. Both plasma cAMP and serum FFA were studied, but no significant changes were found. It is concluded that myocardial cAMP may play an important role in the genesis of ventricular arrhythmias in the acute ischaemic heart and it may be one of the arrhythmogenic factors to evoke ventricular arrhythmias.

Menstrual blood loss, haemoglobin and ferritin concentration of Beijing women wearing steel ring, VCu 200, and TCu 220c IUDs

Menstrual blood loss (MBL), serum ferritin and whole blood cyanmethemoglobin were measured at pre- and 1, 3, 6, 12, 18 and 24th postinsertion cycles in 60 women wearing the Steel Ring, the Copper V (VCu 200) or the Copper T (TCu 220c). The MBL, incidence of menorrhagia and iron deficiency anemia were lower among users of the Steel Ring than among users of the Copper V and T. Anemia occurred later and the duration of menstruation was shorter with the Steel Ring than with the Copper T. There were no statistically significant differences between the Copper V and T.