Exosomal glypican-1 discriminates pancreatic ductal adenocarcinoma from chronic pancreatitis

BACKGROUND AND AIMS

Pancreatic ductal adenocarcinoma (PDAC) diagnosis can be difficult in a chronic pancreatitis (CP) background, especially in its mass forming presentation. We aimed to assess the accuracy of glypican-1-positive circulating exosomes (GPC1+crExos) to distinguish PDAC from CP versus the state-of-the-art CA 19-9 biomarker.

METHODS

This was a unicentric prospective cohort. Endoscopic ultrasound with fine-needle aspiration or biopsy and blood tests (GPC1+crExos and serum CA 19-9) were performed.

RESULTS

The cohort comprised 60 PDAC and 29 CP (7 of which mass forming - MF) patients. Median levels of GPC1+crExos were significantly higher in PDAC (99.7%) versus CP (28.4%; p<0.0001) with an AUROC of 0.96 with 98.3% sensitivity and 86.2% specificity for a cut-off of 45.0% (p<0.0001); this outperforms CA 19-9 AUROC of 0.82 with 78.3% sensitivity and 65.5% specificity at a cut-off of 37 U/mL (p<0.0001). The superiority of% GPC1+crExos over CA 19-99 in differentiating PDAC from CP was observed in both early (stage I) and advanced tumors (stages II-IV).

CONCLUSION

Levels of GPC1+crExos coupled to beads enable differential diagnosis between PDAC and CP including its mass-forming presentation.

Bioecological aspects of triatomines and marsupials as wild Trypanosoma cruzi reservoirs in urban, peri-urban and rural areas in the Western Brazilian Amazon

In the Amazon region, Trypanosoma cruzi transmission cycles involve a great diversity of Triatominae vectors and mammal reservoirs. Some Rhodnius spp. mainly inhabit palm trees that act as microhabitats for hosts and vectors. The current study aimed to describe aspects of the bio-ecology of the vectors and reservoirs of T. cruzi in relation to human populations resident near areas with large quantities of palm trees, in rural, peri-urban and urban collection environments, located in the Western Brazilian Amazon. Rhodnius pictipes and Didelphis marsupialis were respectively the most predominant vector and reservoir, with rates of 71% for R. pictipes and 96.5% for D. marsupialis. The vast majority of T. cruzi isolates clustered with TcI. The most prevalent haplotype was TcI COII1 (69.7%). Mauritia flexuosa and Attalea phalerata were the main ecological indicators of infestation by triatomines. Birds were the most common food source (27,71%). T. cruzi isolated from R. robustus has the haplotype HUM-13, previously detected in a chronic Chagas patient living in the same area. Our results demonstrate the relevance of this study, with the occurrence of elevated infection rates in animals, and suggest the importance of the Amazon zones where there is a risk of infection in humans.

P5008Empagliflozin in a real-world chronic heart failure population

Introduction

Heart Failure (HF) is a burdensome syndrome with significant mortality, morbidity and costs. Its prognosis is further aggravated by diabetes mellitus (DM). The EMPA-REG OUTCOME trial suggested that empagliflozin significantly reduced HF hospitalizations compared to placebo in patients with DM.

Purpose

We aimed to investigate which patients with chronic HF and DM in the outpatient setting could have been enrolled in the main empagliflozin trial.

Methods

This analysis is based on a retrospective cohort enrolling chronic HF patients who consecutively attended the HF appointment between January and July 2018. Of these, those with concomitant DM were selected and further analysed. The key EMPA-REG OUTCOME trial inclusion criteria [(i.e., hemoglobin A1c 7–10%, high cardiovascular (CV) risk and glomerular filtration rate [GFR] ≥30mL/min/1,73m2) were considered. Further, the European Medicine Agency (EMA) restriction (GFR>60mL/min/1,73m2) was also considered in an additional analysis.

Results

Of 316 patients with HF, 114 (36%) concomitantly had DM. Mean age was 74±10 years, 63% were male and most (54%) had preserved left ventricular ejection fraction. Ischemic (51%) and hypertensive (27%) HF were the most often observed etiologies. According to the inclusion criteria, 21 (18.4%) (or 5.3% when further considering the EMA restriction) HF patients could have been potentially enrolled in the main trial and derive a HF hospitalization reduction benefit from starting empagliflozin. The remainder would be excluded due to GFR<30mL/min/1.73m2 (2.6%), absence of “high CV risk” as per trial's definition (7%), HbA1c off target (18,4%) or a combination of the above criteria (53.6%). In light of the new Standards of Medical Care in Diabetes 2019, controlled patients with HbA1c off target (i.e., <7% or >10%) could be switched to a SGLT2 inhibitors, hence possibly expanding the indication to start empagliflozin to 36.8% of our HF cohort.

Figure 1

Conclusions

Roughly 1 in every 5 patients with HF and DM could have been enrolled in the main empagliflozin trial, as per key inclusion criteria, and potentially derive CV benefit from it. Thus, only a minority of our cohort shared the features for EMPA-REG OUTCOME trial inclusion, limiting the extrapolation of the trial's observed CV benefits to our HF cohort. Indeed, whether these benefits also expand to overall HF cohort is eagerly awaited by ongoing trials.

Acknowledgement/Funding

None

Precision enology in Tawny Port wine aging process: Monitoring barrel to barrel variation in oxygen, temperature and redox potential

Tawny Port wine is a category of the famous Portuguese fortified wine commercialized worldwide and produced in the Douro Demarcated Region. Tawny Port wine oxidative aging is a multifactorial process critical for reaching the wanted quality. Real time monitoring of important intrinsic and extrinsic factors that are known to affect both time and quality of the aging process are important to optimize and to manage the natural variability between wines aged in different long-used wood barrels. This study presents the design, development and implementation of a remote distributed system to monitor parameters that are known to be critical for Tawny Port wine aging process. Results indicate that the distributed monitoring system was capable to detect differences between oak wood barrels and between the different storage conditions. Indeed, oxygen and redox potential were the wine's parameters where the differences found between different barrels were greater under the same storage conditions. Considering that Tawny Port wine aging process is oxidative, a variation in the wine's aging process between different wood barrels is to be expected. Actually, significant differences were detected in the oxygen consumption rate amongst the different barrels. Differences in the phenolic composition was also observed in the aged wine (controlled temperature and room temperature).

Liver transplant recipients have a higher prevalence of anal squamous intraepithelial lesions

Background:

Anal squamous intraepithelial lesions (ASIL) are precancerous lesions of anal squamous cell carcinoma, with a higher prevalence in immunosuppressed patients. There are some studies in kidney transplant recipients, but there is no information regarding prevalence in liver transplantation. Our aim was to evaluate the prevalence of ASIL in this setting.

Methods:

Prospective case–control study involving liver transplant recipients without any other known risk factor for ASIL (n=59), which were compared with a healthy control group (n=57). All were submitted to anal cytology and high-resolution anoscopy was performed in those with abnormal results.

Results:

Ten (17%) of liver transplant recipients had abnormal cytological results, seven patients had atypical squamous cells of undetermined significance (ASC-US), one patient had atypical squamous cells that cannot exclude high-grade (ASC-H) and two patients had high-grade squamous intraepithelial lesions (HSIL). In the control group, one patient (2%) had an ASC-US result (P=0.005). Anal squamous intraepithelial lesions were confirmed in 7 out of 10 of liver transplant patients and 0 out of 1 in the controls (P=0.013) by high-resolution anoscopy with biopsies. Current smoking was the only risk factor for abnormal cytology (odds ratio=5.87, 95% confidence intervals=1.22–28.12, P=0.027).

Conclusions:

Liver transplant patients have a higher risk of ASIL. Screening should be considered, especially in smokers.

Acute heart failure and rhabdomyolysis: a clue for the diagnosis of polymyositis with cardiac involvement

Polymyositis is an idiopathic inflammatory myopathy, characterized by proximal muscle weakness and sometimes extramuscular manifestations. We report the case of a 51-year-old male, with history of complete heart block, which required pacemaker implantation, and subsequently heart failure, presenting to the emergency department with worsening of dyspnea and peripheral edema. He was admitted to the Internal Medicine ward with acute heart failure and started on diuretic therapy. During hospitalization, he was discovered to have marked rhabdomyolysis. Examination revealed proximal symmetrical muscle weakness and arthralgia. The immunological study, electromyography and muscle biopsy confirmed polymyositis. The patient was started on prednisolone with clinical improvement and resolution of rhabdomyolysis. The presence of conduction defect, ventricular dysfunction, mitral valve regurgitation, segmental hypokinesia (myocardial scintigraphy without perfusion defects) and pulmonary hypertension, as well as elevated troponin with improvement after specific therapy, points to cardiac involvement. Polymyositis is a rare entity, with an insidious evolution and a myriad of extramuscular features that can mimic other conditions. In particular, cardiac involvement may be the first and only recognized manifestation. The key point for the diagnosis is to contemplate the possibility of polymyositis.

Optical grooming switch with regenerative functionality for transparent interconnection of networks

We demonstrate a regenerative optical grooming switch for buffer-less interconnection of metro/access and metro/core ring networks with switching functionality in time, space and wavelength domain. Key functionalities of the router are the traffic aggregation with time-slot interchanging (TSI) functionality, the WDM-to-ODTM multiplexing and the OTDM-to-WDM demultiplexing of high-speed channel into lower bit-rate tributaries as well as multi-wavelength all-optical 2R regeneration of several higher-speed signals. BER and Q-factor measurements of different switching scenarios show excellent performance with no error floor and Q-factors above 21 dB.

Phytochemical profiles of Targionia lorbeeriana: grown in vitro and in the open

The terpenoid constituents of Targionia lorbeeriana grown in vivo and in vitro were compared. The analysis of the dichloromethane extract was performed by HPLC-UV and by HPLC-MS. The obtained results revealed that the sesquiterpene lactones isolated from the dichloromethane extract of the wild Targionia lorbeeriana were also produced by the liverwort in in vitro cultures, in the same relative amounts. The composition of essential oils was evaluated by GC and GC-MS. Both, the yield and diversity of the essential oil obtained from wild growing T. lorbeeriana gametophytes were higher than those growing in vitro. Although, a significant number of compounds produced in vivo were maintained in vitro, a considerable number of other ones were not detected. Instead, under in vitro conditions, some new compounds were found which do not accumulate under wild conditions.

Spray-drying of the microalga Dunaliella salina: effects on beta-carotene content and isomer composition

The effects of spray-drying of the unicellular microalga Dunaliella salina on its beta-carotene content and geometric isomer composition have been studied. The efficacy of a range of synthetic and natural antioxidants in preventing degradation of beta-carotene has been determined. Losses of beta-carotene and isomerization were minimal during processing for both the control (no exogenous antioxidants) and the samples containing butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). However, the use of tocopherol-based antioxidants resulted in degradation of 52-72% of beta-carotene during the drying process. All dried powders of Dunaliella proved to be unstable during storage in the presence of light and air, with beta-carotene degraded according to a first-order kinetic model. Of the antioxidants studied, only TBHQ was successful in significantly minimizing degradation (degradation constants of 0.03 and 0.04 days(-)(1), compared to 0.53 days(-)(1) for the respective control). For control powders and those with BHT added to the feed, the degradation constants were reduced to values between 0.27 and 0.37 days(-)(1) by restricting light and flushing with nitrogen; however, storage in the dark alone had no effect. For more slowly degrading powders having TBHQ added to the feed, it was clear that degradation of beta-carotene was influenced by both light and oxygen. During storage the 9-cis isomer of beta-carotene was significantly more unstable than the all-trans form. TBHQ was, however, successful in reducing relative losses of this isomer for samples stored in the dark. The results suggest a dominant photodegradative mechanism for the loss of the 9-cis isomer of beta-carotene.

Cloning and characterization of cDNAs encoding chicken mitogen-activated protein kinase kinase type 2, MEK2: downregulation of MEK2 in response to inhibition of mitochondrial DNA expression

The present work was initiated with the aim of identifying nuclear genes whose expression is sensitive to the mitochondrial DNA (mtDNA) status of transformed chicken DU24 cells. We cloned and sequenced cDNAs for the mitogen-activated protein kinase kinase type 2, MEK2, a protein involved in the mitogenic growth factor signal transduction pathway in vertebrates. Sequence comparisons between the chicken protein and its mammalian counterparts indicated that MEK2 proteins are highly conserved among vertebrates. Southern blot analysis of endonuclease-digested genomic DNA from primary chick embryo fibroblasts (CEF) suggested that MEK2 is a single-copy gene in this vertebrate species. The steady-state level of MEK2 transcripts is decreased in DUS3 mtDNA-less (rho0) cells developed by long-term exposure of DU24 rho+ cells to ethidium bromide (EtdBr). Run-on in vitro transcription assays and mRNA stability studies indicated that the decrease in MEK2 mRNA content is associated with post-transcriptional regulation. In parental DU24 cells, MEK2 mRNA content decreased after inhibition of mtDNA transcription by EtdBr and inhibition of translation on mitoribosomes by chloramphenicol (CAM). Cytoplasmic hybrids (cybrids) constructed by fusion of chicken rho0 cells with enucleated parental cells and CEF recovered a basal level of MEK2 expression. The MEK2 protein content is decreased in DUS3 rho0 cells and in parental DU24 rho+ cells treated with EtdBr and CAM for 6 days, while that of MEK1, a closely related kinase, remained unchanged. On the basis of these observations, we propose that mitochondria participate in the mitogenic signal transduction pathway in chicken cells through regulation of MEK2 expression.

Digoxigenin-labeled peptides for the immunological quantification of intracellular signaling proteins: application to the MAP kinase kinase isoform MEK2

Two competitive enzyme immunoassays using digoxigenin-labeled peptides have been developed for the quantification of the protein kinase MEK2 in cell extracts. Rabbit polyclonal antibodies directed against either the amino-terminal or proline-rich amino acid sequences of MEK2 were used for the immunoconcentration of the protein. Anti-digoxigenin Fab fragments labeled with horseradish peroxidase allowed the detection of the immune complexes. Amino-terminal and proline-rich enzyme immunoassays exhibited a sensitivity level of 63 and 71 fmol/mL, respectively, and displayed a half-maximal saturation value of 1320 and 1780 fmol/mL. The intra- and inter-assay coefficients of variation for both assays assessed at three different concentrations of MEK2 were lower than 6% and 12%, respectively. The amount of MEK2 measured by the two methods demonstrated an excellent correlation with the expression level of the protein detected by immunoblot analyses when tested on different cell lysates.

Up-regulation of nuclear genes in response to inhibition of mitochondrial DNA expression in chicken cells

Vertebrate cells depleted of (rho0) mitochondrial DNA (mtDNA) exhibited phenotypic traits that differed from the parental (rho+) cells. To isolate genes whose expression is associated with mtDNA depletion, we constructed cDNA libraries from mRNAs isolated from chicken rho+ cells transformed by the MC29 (v-myc-containing) retrovirus and from rho0 cells developed by long-term exposure of the rho+ cells to ethidium bromide (EtdBr). Through subtractive hybridization procedures, three genes, elongation factor 1 alpha (EF- 1 alpha), beta-actin and v-myc were identified and found to be up-regulated in rho0 cells. In addition, Northern analysis demonstrated that the mRNA content for GAPDH was also elevated in rho0 cells. Run-on transcription assays and mRNA stability studies in the presence of actinomycin D indicated that elevated expression of these four genes depends, at least in part, upon increased rate of transcription. Other regulatory mechanisms contribute to the elevated expression of the transcripts in rho0 cells, as suggested by cycloheximide enhancement of the accumulation of the mRNAs for EF-1 alpha and beta-actin in rho0 cells, but not in parental rho+ cells. Moreover, inhibition of mtDNA replication and transcription by EtdBr and inhibition of translation on mitoribosomes by chloramphenicol also increased the expression of the four genes in parental rho+ cells, thus mimicking the situation in rho0 cells. These data suggest that information encoded within mtDNA participates in the regulation of nuclear genes in chicken cells.

Zidovudine potentiates local and systemic inflammatory responses in the rat

The effect of chronic treatment with zidovudine (AZT) on the inflammatory response was examined in the rat. AZT was administered orally for 36 days. On day 35, inflammation was induced by hindpaw injection of 1% carrageenan lambda. Paw edema over a 24-hour period was used as a marker of the local inflammatory reaction. On day 36, quantification of immunoreactive T-kininogen and alpha 1-inhibitor-3 in liver and serum was used to assess the systemic inflammatory response. Albumin was selected as a protein whose concentration is modified only slightly or not at all during the acute-phase response. Animals treated with AZT transiently exhibited significantly greater (18%) paw edema 3 hours after carrageenan injection. AZT treatment alone induced a 1.8-fold increase in serum T-kininogen concentration, but it had no effect on albumin and alpha 1-inhibitor-3. In rats with inflamed paws, AZT administration led to a significant increase in liver (3.4-fold) and serum (1.8-fold) immunoreactive T-kininogen content. Dot blot analysis of total RNA isolated from liver correlated with the protein measurements. Our results indicate that chronic treatment with AZT potentiates the nonspecific local and the systemic inflammatory responses in the rat.

Dynamical change of mitochondrial DNA induced in the living cell by perturbing the electrochemical gradient

Digital-imaging microscopy was used in conditions that allowed the native state to be preserved and hence fluorescence variations of specific probes to be followed in the real time of living mammalian cells. Ethidium bromide was shown to enter into living cells and to intercalate stably into mitochondrial DNA (mtDNA), giving rise to high fluorescence. When the membrane potential or the pH gradient across the inner membrane was abolished by specific inhibitors or ionophores, the ethidium fluorescence disappeared from all mtDNA molecules within 2 min. After removal of the inhibitors or ionophores, ethidium fluorescence rapidly reappeared in mitochondria, together with the membrane potential. The fluorescence extinction did not result from an equilibrium shift caused by leakage of free ethidium out of mitochondria when the membrane potential was abolished but was most likely due to a dynamical mtDNA change that exposed intercalated ethidium to quencher, either by weakening the ethidium binding constant or by giving access of a proton acceptor (such as water) to the interior of mtDNA. Double labeling with ethidium and with a minor groove probe (4',6-diamino-2-phenylindole) indicated that mtDNA maintains a double-stranded structure. The two double-stranded DNA states, revealed by the fluorescence of mitochondrial ethidium, enhanced or quenched in the presence of ethidium, seem to coexist in mitochondria of unperturbed fibroblast cells, suggesting a spontaneous dynamical change of mtDNA molecules. Therefore, the ethidium fluorescence variation allows changes of DNA to be followed, a property that has to be taken into consideration when using this intercalator for in vivo as well as in vitro imaging studies.

Chloramphenicol and the inflammatory response in the rat. Upregulation of the gene for T2-kininogen in liver

Recent observations have indicated that cytokine and glucocorticoid mediators of the inflammatory response in mammals interfere with mitochondrial respiratory capacity of cultured cells. Here, we report studies on the effect of the antibiotic chloramphenicol (CAP), a potent mitochondrial protein synthesis and respiratory inhibitor, on the inflammatory response in the rat. CAP was injected daily (i.p.) at doses of 30, 100 and 300 mg kg-1 during a period of 10 days. Acute inflammation was induced on day 10 by s.c. injection of carrageenan into the hindpaws. Paw edema reaction and liver and serum expression of the acute phase protein T-kininogen were used as markers of the local and systemic inflammatory response, respectively. Albumin was selected as a liver protein whose expression is little or not affected in inflamed rats. We found that the swelling process induced locally by carrageenan injection was significantly altered in rats treated with CAP at the dose level of 300 mg kg-1. The inhibitory effect of CAP was transient, extending up to 3 hr after carrageenan injection. CAP was observed also to alter the mitochondrial respiratory capacity of liver cells, reducing cytochrome C oxidase activity up to 50%. In contrast, liver immunoreactive T-kininogen content and the T2-kininogen mRNA steady-state level were found to increase in a dose-related manner in CAP-treated animals. These values were slightly different from those recorded in control rats inflamed with carrageenan. No significant increase of T-kininogen serum content was seen at all dose levels of CAP injected. Among inflamed animals, those exposed long-term to CAP had elevated liver and serum T-kininogen content and t2-kininogen mRNA steady-state levels. Expression of the gene for albumin was not affected in rats treated or not with CAP. The present observations indicate that CAP influences both local and systemic inflammatory responses in the rat.

Bradykinin decreases T-kininogen synthesis in a rat hepatoma cell line: evidence of bradykinin B2-type receptors

Using the rat H4-II-E-C3 hepatoma cell line, we investigated the presence of [125I][Tyr8]BK binding sites and the direct modulation of T-kininogen synthesis, an acute phase protein of inflammation, by bradykinin (BK) analogues. H4-II-E-C3 membrane preparations exhibited [125I][Tyr8]BK binding sites with a Kd of 4 nM and a Bmax of 120 fmol/mg of protein. Des-Arg9-BK showed no affinity (Ki > 10(-4) M) for these sites. The B2 metabolism-resistant and selective agonist [Phe8 psi (CH2-NH)Arg9]BK decreased the T-kininogen concentration in H4-II-E-C3 medium by 23% (p < 0.05). This effect was reversed by coincubation with the B2 antagonist HOE140. The B1 agonist Sar[D-Phe8]des-Arg9-BK and the B1 antagonist Lys[Leu8]des-Arg9-BK did not modify T-kininogen concentrations. The interaction between cytokines and kinins in the modulation of T-kininogen synthesis was also studied. Preincubation of hepatoma cells for 1 h with interleukin-1 alpha (IL-1 alpha) alone reduced T-kininogen concentrations by 37%, and this effect was blocked by co-addition of HOE140. Preincubation with interleukin-6 (IL-6) increased T-kininogen levels by threefold. Coincubation in the presence of the B2 agonist decreased this augmentation by 24%. The latter effect was reversed by co-addition of HOE140. None of the cytokines tested induced a response to the B1 agonist or antagonist under the experimental conditions studied. Overall, these results support the presence of a functional B2 receptor on H4-II-E-C3 cells that modulates T-kininogen synthesis. We suggest that the receptor is involved in vivo in a retroaction loop between kinins and T-kininogen production during inflammation. We speculate that BK could be a mediator in the modulation of acute phase protein synthesis by the cytokines IL-1 alpha and IL-6.

A role for B1 and B2 kinin receptors in the modulation of T-kininogen during the acute phase response of inflammation

Kinin antagonists at B1 and B2 receptors were examined on liver and serum concentrations of immunoreactive T-kininogen and its gene expression in a rat model of carrageenan-induced hindpaw edema. Whereas the B2 antagonist, HOE140, dose-dependently inhibited the paw edema induced by intraplantar injection of carrageenan, the B1 receptor agonist [Sar(D-Phe8)des-Arg9]BK and antagonist [Lys(Leu8)des-Arg9]BK were ineffective. On its own, HOE140 (3.25 x 10(-7) mol/ paw, intraplantar) had no effect on liver and serum T-kininogen levels but it significantly enhanced liver T-kininogen concentrations in rats pretreated with carrageenan at 8 and 24 h postinjection. In the liver, the most pronounced effect was seen at 24 h (treated 248 +/- 7 micrograms/g vs. untreated 113 +/- 9 micrograms/g). The same dose of HOE140 increased serum T-kininogen from 1255 +/- 57 to 1696 +/- 83 micrograms/ml at 24 h. HOE140 did not affect tissue albumin content during the same period. Transcript measurements revealed that the steady-state level of liver T2-kininogen mRNA was specifically increased by HOE140 during inflammation. In carrageenan-treated rats, the B1 antagonist [Lys(Leu8)des-Arg9]BK also significantly increased liver T-kininogen at 24 h. The present results support a role for B2 kinin receptors in the early phase of acute phase protein synthesis and of both B2 and B1 receptors in the late phase (24 h). Hence, systemic effects of kinins should be taken into account in the pharmacology and physiopathology of B1 and B2 kinin receptors in inflammation.

Chicken acidic ribosomal phosphoprotein PO: isolation and molecular characterization of cDNA clones

Differential screening of a cDNA library prepared from chicken mitochondrial DNA-less cells led to the isolation of the acidic phosphoprotein PO, as inferred from similar sequences from human, rat and mouse deposited in databases. The chicken PO protein is highly conserved among vertebrates. Nucleotide identities between the chicken and mammalian cDNA sequences are greater than 94%. Amino acid sequence identities greater than 92% are observed between the chicken protein and its mammalian counterparts, and when changes to conservative amino acids are considered, similarities range from 99.4 to 100%. The gene evolved mainly by silent transitions occurring at the third codon position. The highly antigenic carboxy-terminal sequences of mammalian PO proteins are identical to that of the chicken. Southern blot analysis of restricted DNA from chicken embryo fibroblasts suggests that only one gene encoding PO exists in the chicken genome. By Northern analysis, the PO probe detects a major RNA species 1.1-kilobases long, and a minor species 4.0-kilobases long which has no equivalent thus far in mammals.

Tumor-forming ability in athymic nude mice of human cell lines devoid of mitochondrial DNA

We have examined the contribution of the mitochondrial genome to the tumorigenic phenotype expressed by human cell lines derived from an ovarian and a cervical carcinoma and from an osteogenic sarcoma. All these continuous cell lines are anchorage-independent in soft agar and form tumors in athymic nude mice. Long-term exposure of the cells to ethidium bromide, an intercalating agent which inhibits mitochondrial DNA replication, gave rise to subclones depleted of mitochondrial DNA and RNA molecules and displaying either anchorage independence or dependence. These respiratory-deficient subclones contain disorganized and enlarged mitochondria, are auxotrophic for uridine and pyruvate, and grow in vitro at a rate nearly identical or moderately slower than their respective parent. The tumor-forming ability of both anchorage-independent and -dependent cell lines was tested by s.c. and intramuscular implantation of the cells in nude mice. We found that the tumorigenic capacity was influenced by the route of inoculation. Subcutaneously, mitochondrial DNA-less cell lines are either poorly or nontumorigenic, while all but one cell line form tumors when implanted into the hind leg muscle. The relative in vivo growth rate of the parent and the mitochondrial DNA-less subclones reflects their respective in vitro rate of growth. All intramuscular tumors introduced into culture mimic the molecular and phenotypic traits of the injected cells, with the exception of the anchorage-dependent cell lines which give rise to anchorage-independent tumor cell lines. The present observations indicate that human cells without mitochondrial DNA have the capacity to proliferate and form tumors in vivo.

Evolution of the WANCY region in amniote mitochondrial DNA

In most vertebrate mitochondrial genomes, the site for initiation of light-strand replication, OL, is found within a cluster of five transfer RNA (tRNA) genes (tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), and tRNA(Tyr)). This region and part of the adjacent cytochrome c oxydase subunit I (COI) gene were sequenced for two crocodilian, two turtle, and one snake species and for Sphenodon punctatus; part of the adjacent nicotinamide adenine dinucleotide dehydrogenase subunit 2 (ND2) gene was also sequenced for the crocodilian and turtle species. All had the typical vertebrate gene order. The turtles and the snake have a lengthy noncoding sequence between the tRNA(Asn) and tRNA(Cys) genes that we assumed to be homologous to the mammalian OL. The crocodilians and Sphenodon lack such a sequence, a condition they share with birds. Most proposed phylogenies for the amniotes require that OL at this position was lost at least twice during their diversification or was evolved independently more than once. Within the five tRNA genes, frequencies of substitutions are much higher in loops than in stems. Many loops vary dramatically in size among the species; in the most extreme case, the D-arm of the Sphenodon tRNA(Cys) is a "D-arm replacement" loop of seven nucleotides. Frequency of transitions in stems is relatively uniform across tRNAs, but frequency of transversions varies greatly. Mismatches in stems are infrequent, and their relative frequency in a specific tRNA is unrelated to the frequency of substitution in the corresponding gene. Several features of mammalian mitochondrial tRNAs are conserved in WANCY tRNAs throughout amniotes. The inferred initiation codon for COI is GTG in crocodilians, turtles, and the snake, a condition they share with fishes, certain amphibians, and birds. TTG appears to be the initiation codon for COI in Sphenodon; if correct, this would be a novel initiation codon for vertebrate mitochondrial DNA. Phylogenetic analyses of the inferred amino acid sequences of ND2 and COI support the sister-group relationship of birds and crocodilians and suggest that mammals are an early derived lineage within the amniotes.

Cloning and characterization of a cDNA encoding elongation factor 1 alpha from chicken cells devoid of mitochondrial DNA

Using a subtractive hybridization procedure, we isolated a cDNA clone encoding elongation factor 1 alpha (EF-1 alpha) from chicken cells devoid of mitochondrial (mt) DNA (rho0). The sequence encodes 1691 nucleotide (nt) residues and contains an open reading frame of 463 codons. Compared with the sequences from human, mouse and Xenopus laevis, the highest degree of sequence identity is detected in the 3' untranslated (> 90%) and coding (> 85%) regions. The gene evolved mainly by transitions occurring at the third codon position. Most transitions are silent and amino acid (aa) sequence identities are greater than 95%. Comparison of the protein domains interacting with cellular components (GTP/GDP, tRNAs and beta-actin) reveals that they are highly conserved in species belonging to the four traditional eukaryotic kingdoms. The expression of the EF-1 alpha transcript is elevated in chicken rho0 cells. A single RNA band at 1800 nt is observed in both parental and rho0 cells. Southern blot analysis of restricted DNA from chick embryo fibroblasts (CEF) suggests that only one gene encoding EF-1 alpha exists in the chicken genome.

Nucleotide sequence of the hemG gene involved in the protoporphyrinogen oxidase activity of Escherichia coli K12

The hemG gene of Escherichia coli K12 is involved in the activity of protoporphyrinogen oxidase, the enzyme responsible for the conversion of protoporphyrinogen IX into protoporphyrin IX during heme and chlorophyll biosynthesis. The gene is located at min 87 on the genetic map of E. coli K12. The hemG gene was isolated by a mini-Mu in vivo cloning procedure. As expected, the hemG gene is able to restore normal growth to the hemG mutant, and the transformed cells display strong protoporphyrinogen oxidase activity. Sequencing of the hemG gene allowed us to identify an open reading frame of 546 nucleotides (181 amino acids), within the minimal fragment able to complement the mutant. The presumed molecular mass of the HemG protein is 21,202 Da, in agreement with values found by SDS-PAGE, in a DNA-directed coupled transcription-translation system. The identity of the first 18 amino acids at the amino-terminal end of the protein was confirmed by microsequencing. To our knowledge, this is the first cloning of a gene involved in the protoporphyrinogen oxidase activity of E. coli.

Molecular characterization and evolution of a duck mitochondrial genome

We sequenced 6,478 bp of mitochondrial DNA from Peking duck (Anas platyrhyncos). Eight protein genes, 11 tRNAs, part of the small and large ribosomal subunits, and the control region sequences were compared to homologous chicken sequences. The gene organization in duck and chicken is identical but differs from other vertebrates in the juxtaposition of the tRNA(Glu)-ND6 genes next to the control region and in the lack of a hairpinlike structure between the genes for tRNA(Asn) and tRNA(Cys) used for light-strand replication. Protein, tRNA, and rRNA genes evolved mainly through base substitutions and small insertions and deletions. Transitions greatly outnumber transversions in the tRNA and rRNA genes, but this bias is not evident in protein genes; the control region has a higher proportion of transversions. The duck and chicken control regions show a high frequency of length mutations. Large A-T-rich nucleotide stretches dispersed across the region between the bidirectional transcription promoter and the heavy-strand replication origin in the chicken are absent in the duck. Sequence elements for heavy-strand replication in mammals are conserved in the duck and chicken control regions. Estimates of divergence for ribosomal RNAs and proteins based on total substitutions, transversions, and amino acid replacements show that all the duck/chicken values are lower than the corresponding mammal/mammal (cow, human, mouse) values. If paleontological data suggesting that avian and eutherian ordinal radiation occurred at approximately the same time are correct, this suggests that at great evolutionary distance, rate of mitochondrial DNA evolution in birds is somewhat decelerated compared to mammals.

Stereology of the pterygopalatine ganglion of the rat

The right pterygopalatine ganglia (PG) of 9 male Wistar-strain rats were dissected, embedded in Epon (3 specimens) or paraffin (6 specimens), and prepared for stereological examination under light microscopy. The perikarya were quantitatively characterized, and the ganglionic volume was determined. Stereology is an efficient method for the quantitative evaluation of the perikarya of the PG. The results(expressed as mean +/- standard deviation) were: a) areal fraction occupied by the perikarya = 53.8 +/- 7.4%; b) the perikaryal surface area per volume = 0.101 +/- 0.013 microns-1; c) the number of perikarya per volume x 10(-5) = 5.26 +/- 0.99 microns-3; d) the mean profile area of the perikarya (apk) = 505.93 +/- 78.29 microns 2; e) the mean perikaryal volume (vpk) = 9,179.33 +/- 1,533.52 microns 3; and f) the ganglionic volume = 0.210 +/- 0.127 mm3. The low coefficient of variation the apk and vpk values suggests the presence of only one population of neurons in the PG of the rat. The number of perikarya in the PG is about 11,046 per ganglion. As compared to analogous data in the otic ganglion of the rat, the PG did not show statistically significant stereological differences, but the relatively higher number of neurons found in the PG is probably associated with the higher functional activity of this ganglion.

On the tumorigenicity of mitochondrial DNA-depleted avian cells

We have examined the tumorigenic potential of mitochondrial DNA-depleted (mtDNA-) cells derived from the tumorigenic chicken cell line DU24. The mtDNA- cells were unable to proliferate in the wing web of day-old chicks. Cytoplasmic hybrids resulting from crosses between the mtDNA- whole cells and cytoplasts from enucleated parental cells (mtDNA+) recover both mtDNA and tumorigenicity. These results are in accordance with those obtained in prior experiments where mtDNA was shown to modulate the anchorage-independent phenotype of transformed avian cells.

The transcription of DNA in chicken mitochondria initiates from one major bidirectional promoter

Transcription start sites of chicken mitochondrial DNA have been mapped in the control region by direct sequencing of in vitro capped mitochondrial RNA species, by primer extension and by S1 nuclease protection analysis. Transcription of the heavy strand initiates predominantly at a site 156 nucleotides upstream of the tRNA(Phe) gene, i.e. about 135 nucleotides further upstream than the corresponding sites in amphibia and mammals. On the opposite strand, transcription starts predominantly one nucleotide removed from the site in the heavy strand. The L-strand position start site is similar to that found in other vertebrates. The chicken mitochondrial DNA control region thus contains one major transcriptional promoter, whose bidirectional capacity is similar to the situation in amphibia but which contrasts to the mainly unidirectional capacity of mammalian promoters. In chicken mitochondria, the sequence comprising the start sites is A + T rich and contains an almost perfect inverted repeat which can be folded into a cruciform structure. The heavy and light strand initiation sites are flanked on their respective 3' ends by an octanucleotide sequence matching those surrounding the start sites in Xenopus laevis (5'-ACPuTTATA-3'). This motif is found associated with the H-strand start sites in mouse but is not present in human nor bovine mitochondrial DNA promoters.

Nucleotide sequence and evolution of coding and noncoding regions of a quail mitochondrial genome

Segments of the Japanese quail mitochondrial genome encompassing many tRNA and protein genes, the small and part of the large rRNA genes, and the control region have been cloned and sequenced. Analysis of the relative position of these genes confirmed that the tRNA(Glu) and ND6 genes in galliform mitochondrial DNA are located immediately adjacent to the control region of the molecule instead of between the cytochrome b and ND5 genes as in other vertebrates. Japanese quail and chicken display another distinctive characteristic, that is, they both lack an equivalent to the light-strand replication origin found between the tRNA(Cys) and tRNA(Asn) genes in all vertebrate mitochondrial genomes sequenced thus far. Comparison of the protein-encoding genes revealed that a great proportion of the substitutions are silent and involve mainly transitions. This bias toward transitions also occurs in the tRNA and rRNA genes but is not observed in the control region where transversions account for many of the substitutions. Sequence alignment indicated that the two avian control regions evolve mainly through base substitutions but are also characterized by the occurrence of a 57-bp deletion/addition event at their 5' end. The overall sequence divergence between the two gallinaceous birds suggests that avian mitochondrial genomes evolve at a similar rate to other vertebrate mitochondrial DNAs.

Transplantability of myelocytomatosis MC29 virus-producing cell lines in chicken. Lateral transformation of host cells

The transplantability of myelocytomatosis MC29 virus-producing chicken cell lines BR-3 and OB-1 was examined in 1-day-old chicks. Both cell lines, derived from the chicken cell line DU249, harbor nuclear genetic markers for drug resistance. When these cells were inoculated subcutaneously in the wing web of chicks, tumors developed at the site of injection in 65% of the cases. Propagation in culture of cells obtained by dispase treatment of the excised tumors, followed by selection for drug resistance, revealed that only a fraction of the tumors (27% and 60% for BR-3 and OB-1, respectively) resulted from the growth of the injected cells. The other tumors derive from the proliferation of host cells transformed by MC29 virus released by the injected cells. Tumor development subsequent to similar inoculation of 1-day-old chicks with cell-free virus stock further confirmed the tumorigenic capacity of MC29 at the site of injection. These results underline the need for the determination of tumor cell origin in studies using MC29-producing cell lines and highlight the advantage of using cells with drug-resistant markers for such work. In the course of this study we determined by immunohistochemical criteria, the myogenic origin of some of the virally induced tumors. This is the first report of in vivo transformation of muscle cells by MC29-containing virus stocks in the newly hatched chick.

Mitochondrial DNA modulation of the anchorage-independent phenotype of transformed avian cells

The progressive loss of mitochondrial DNA in the presence of ethidium bromide in immortal avian cell lines correlates with a decrease in their potential for anchorage-independent growth in soft agar. In short-term treated cells, this effect is reversible and the recovery of cloning potential parallels the recovery of control levels of mitochondrial DNA. Long-term ethidium-bromide-treated cells are permanently respiration-deficient and display anchorage-dependent growth. Anchorage-independent revertants can be selected, suggesting that the lack of a respiratory chain per se might not be responsible for the inability of mitochondrial DNA-depleted cells to grow in soft agar. Cybrids formed from the fusion of mitochondrial DNA-depleted, anchorage-dependent cells to cytoplasts from parental cells are capable of growth in soft agar. The mitochondria-specific inhibitor, rhodamine 6G, prevents the recovery of the anchorage-independent phenotype in similar hybrids. These results suggest that mitochondrial DNA is required to maintain the transformed phenotype of avian cells.

Gene organization of the Peking duck mitochondrial genome

The gene organization of the Peking duck mitochondrial (mt)DNA has been deduced through heterologous hybridization using different cloned fragments of the chicken or Japanese quail mitochondrial genome as probes. As in the chicken, and other gallinaceous birds, the Peking duck mtDNA displays a novel gene order which differs from that of other vertebrates by the unusual localization of the tRNA(Glu) and ND6 genes next to the displacement (D) loop region of the molecule. The position of these genes with respect to the mitochondrial D-loop region, the cytochrome oxidase subunits I, II and III, the NADH dehydrogenase subunit I and the ribosomal (r) RNAs, was confirmed by the partial nucleotide sequence of cloned mtDNA fragments.

Sequence and gene organization of the chicken mitochondrial genome. A novel gene order in higher vertebrates

The 16,775 base-pair mitochondrial genome of the white Leghorn chicken has been cloned and sequenced. The avian genome encodes the same set of genes (13 proteins, 2 rRNAs and 22 tRNAs) as do other vertebrate mitochondrial DNAs and is organized in a very similar economical fashion. There are very few intergenic nucleotides and several instances of overlaps between protein or tRNA genes. The protein genes are highly similar to their mammalian and amphibian counterparts and are translated according to the same variant genetic code. Despite these highly conserved features, the chicken mitochondrial genome displays two distinctive characteristics. First, it exhibits a novel gene order, the contiguous tRNA(Glu) and ND6 genes are located immediately adjacent to the displacement loop region of the molecule, just ahead of the contiguous tRNA(Pro), tRNA(Thr) and cytochrome b genes, which border the displacement loop region in other vertebrate mitochondrial genomes. This unusual gene order is conserved among the galliform birds. Second, a light-strand replication origin, equivalent to the conserved sequence found between the tRNA(Cys) and tRNA(Asn) genes in all vertebrate mitochondrial genomes sequenced thus far, is absent in the chicken genome. These observations indicate that galliform mitochondrial genomes departed from their mammalian and amphibian counterparts during the course of evolution of vertebrate species. These unexpected characteristics represent useful markers for investigating phylogenetic relationships at a higher taxonomic level.

Histidine tRNA from chicken mitochondria has an uncoded 5'-terminal guanylate residue

In an attempt to identify the transcription initiation sites in chicken mitochondrial DNA, RNAs capped in vitro using vaccinia guanylyl transferase and [alpha-32P] GTP were analyzed. The most abundant labeled transcript was identified by RNA sequencing as the mitochondrial tRNA(His). Sequence analysis also revealed that this tRNA contains an extra guanylate residue at its 5' end, characteristic of the histidine tRNA family. The respective genomic region was also cloned and sequenced. In contrast to bacteria and the mitochondria of fungi and plants, the extra G of chicken mitochondrial tRNA(His) is not encoded in the gene. Therefore, the guanylate residue must be added post-transcriptionally, as demonstrated for the nuclear tRNA(His) in yeast and Drosophila. Analysis of a capped tRNA(His) precursor of chicken mitochondria suggests that addition of the extra G occurs independently of 3' end maturation. Since in the chicken mitochondrial tRNA(His) the extra G can be efficiently labeled by the capping assay, it should possess a 5'-terminal di- or triphosphate, which contrasts to the 5'-terminal monophosphate proposed for the nuclear encoded tRNA(His). Our results imply that the ability of a mitochondrial RNA to be capped in vitro does not necessarily prove that it contains a transcription initiation site.

Putative chicken "muscle-specific 7 S RNA" is related to the mitochondrial ATPase 6 gene

Sequence analysis of the mitochondrial ATPase 6 gene from chicken revealed that its 3' region is virtually identical with a chicken muscle-specific 7 S RNA which was reported to induce the expression of tissue-specific functions in blastoderm explants. Using chicken and quail cell lines depleted of mitochondrial DNA, we demonstrate that the 7 S RNA is encoded by the mitochondrial genome and not by nuclear (repetitive) DNA as suggested previously. Moreover, no 7 S RNA-homologous transcript of the expected length (about 400 bases) is detected, either in these cell lines or in heart and liver tissues. The only RNA species hybridizing with a 7 S RNA-specific probe is an abundant, 900 base long transcript of mitochondrial origin that we identify as the ATPase 8-ATPase 6 fused messenger. We suggest that the characterized muscle-specific 7 S RNA cDNA is derived from an unrelated contaminant in the blastoderm-inducing fraction.

[Experience and results with a lactate dehydrogenase marker in vaginal secretions of women at high risk for endometrial cancer]

The authors present and discuss the results obtained with 202 Gynaegnost experiments in 161 women, between 45 and 65 years, nulliparous, or having experienced a late pregnancy, with menopause occurring after the age of 52 and undergoing or not estrogen-therapy after menopause, and presenting high blood pressure, obesity or diabetes. The purpose of this multicenter study, to be continued, was to demonstrate the efficacy of this tumor marker, in the early diagnosis of endometrial carcinoma, in high-risk women.

Development and characterization of continuous avian cell lines depleted of mitochondrial DNA

Populations of quail and chicken cells were treated with ethidium bromide, an inhibitor of mitochondrial DNA replication. After long-term exposure to the drug, the cell populations were transferred to ethidium bromide (EtdBr)-free medium, and cloned. Clones HCF7 (quail) and DUS-3 (chicken) were propagated for more than a year, and then characterized. Analysis of total cellular DNA extracted from these cells revealed no characteristic mitochondrial DNA molecule by Southern blot hybridization of HindIII- or AvaI-digested total cellular DNA probed with cloned mitochondrial DNA fragments. Reconstruction experiments, where a small number of parental cells was mixed with HCF7 cells and DUS-3 cells before extraction of total cellular DNA, further strengthen the notion that the drug-treated cells are devoid of mitochondrial DNA molecules. The cell populations were found to proliferate at a moderately reduced growth rate as compared to their respective parents, to be auxotrophic for uridine, and to be stably resistant to the growth inhibitory effect of EtdBr and chloramphenicol. At the ultrastructural level, mitochondria were considerably enlarged and there was a severe reduction in the number of cristae within the organelles and loss of cristae orientation. Morphometric analysis revealed a fourfold increase of the mitochondrial profile area along with a twofold decrease of the numerical mitochondrial profiles. Analysis of biochemical parameters indicated that the cells grew with mitochondria devoid of a functional respiratory chain. The activity of the mitochondrial enzyme dihydroorotate dehydrogenase was decreased by 95% and presumably accounted for uridine auxotrophy.

Development and characterization of mutant chicken cell lines for somatic cell genetics studies

A series of stable mutants bearing nuclear genetic markers were developed from the established chicken cell line DU24. The mutants were obtained after mutagenesis of DU24 cells with ethyl methanesulfonate (EMS) or arose spontaneously when plated in the appropriate selective medium. Clones resistant to 5-bromodeoxyuridine (BrdU) were obtained following a two-step selection procedure and analyzed. The BrdUr cells were found to be deficient in thymidine kinase activity and were HAT sensitive. Molecular characterization of these mutants revealed no deletions or other rearrangements, but methylation of some cytosine residues was decreased in the mutants. A similar restriction profile was seen in a series of mutants made resistant to BrdU after cultivation of DU24 cells in increasing concentrations of the drug over a period of six months. Selection of EMS-treated BrdUr cells in 10 microM ouabain gave rise to a clone resistant to both drugs and which was still HAT sensitive. Clones resistant to 6-thioguanine were also isolated, but showed wild-type hypoxanthine phosphoribosyltransferase activity and were HAT resistant. A number of the cell lines isolated were found to be suitable for fusion experiments with both chicken cells and cells from other vertebrate species.

An established avian fibroblast cell line without mitochondrial DNA

An established avian fibroblast cell line (LSCC-H32) has been found to be inherently resistant to the growth-inhibitory effect of ethidium bromide, when supplied with exogenous uridine. After long-term exposure to ethidium bromide (90 days), the cell population has been transferred to drug-free medium for 60 days, and then seeded at low cell density. Three clones have been isolated and propagated in drug-free medium for 5, 6, and more than 12 months, respectively. It was found that none of these cell lines had detectable cytochrome c oxidase activity and that they were virtually devoid of cytochromes aa3 and b. Mitochondrial DNA was quantitated by DNA-DNA reassociation kinetics with a probe of chicken liver mitochondrial DNA. A mean number of 300 copies of mitochondrial DNA per cell was found in LSCC-H32 cells. Analysis of DNA extracted from cell populations exposed to ethidium bromide for 90 days and then transferred to drug-free medium for long periods of time revealed no mitochondrial DNA molecules by reassociation kinetics or by Southern blot hybridization of HindIII-or AvaI-digested total cellular DNA.

Degenerative changes, DNA synthesis and mitotic activity in rat liver following single exposure to diethylnitrosamine

Degenerative and regenerative changes induced in rat liver by single exposure to diethylnitrosamine (DEN) were examined by morphological and biochemical approaches. Apoptotic changes were observed in livers of rats exposed to a 'subnecrogenic' dose of DEN (10 mg/kg) as well as in liver parenchyma of those receiving a necrogenic dose (100 mg/kg). Zonal centrilobular necrosis was observed exclusively in the latter group. Regenerative changes, i.e., increases in DNA synthesis, labeling index and mitotic activity, occurred only in animals exposed to the higher dose. The mitogenic effect obtained in these conditions was about half that induced by two-thirds hepatectomy and the maximum response occurred about 24 h later than in partially hepatectomized rats.