Clinical Significance of Disseminated Pluripotent Tumor Cell Signature Expression in the Bone Marrow from Patients with Colorectal Cancer

Purpose:

Disseminated tumor cells (DTCs) are critically involved in tumor relapse and survival in several invasive tumors. We previously showed that the ATP-binding cassette (ABC) transporter, ABCB5, is a chemoresistance mediator expressed on specific cell subsets in colorectal cancer (CRC) and other malignancies. This study evaluated the molecular signature expression and its clinical relevance of DTCs in bone marrow from patients with colon cancer.

Methods:

This study included 49 consecutive patients (UICC stage I-IV) that underwent curatively intended or palliative surgery for CRC. We analyzed cells from bone marrow aspirates obtained before surgery and derived from patients that had completed minimally a 5-year follow-up. The gene expression of ABCB5 in comparison to CD133 (molecule for identifying cancer initiating cells), Lgr5 (an intestinal stem cell marker) as well as Cytokeratin (CK) 20 (terminally differentiated tumor cells of epithelial origin) in these cells was evaluated.

Results:

Bone marrow analysis showed differential expression between the analyzed genes. ABCB5 and Lgr5 and to lesser extent CD133 and CK20 genes were significantly expressed in the analyzed cells from bone marrow aspirates while only ABCB5 and Lgr5 were significantly negative associated with tumor progress and overall survival.

Conclusion:

Overexpression of ABCB5 and Lgr5 in bone marrow negatively influenced patient survival pointing to a specific chemo resistant and pluripotent cell subgroup of DTCs in the bone marrow. ABCB5 like Lgr5 positive cells seem to be involved in limited tumor related patient survival, suggesting that ABCB5- and Lgr5-positive cells may be relevant for specific clinical intervention strategies

Toll Like Receptor 2, 4, and 9 Signaling Promotes Autoregulative Tumor Cell Growth and VEGF/PDGF Expression in Human Pancreatic Cancer

Toll like receptor (TLR) signaling has been suggested to play an important role in the inflammatory microenvironment of solid tumors and through this inflammation-mediated tumor growth. Here, we studied the role of tumor cells in their process of self-maintaining TLR expression independent of inflammatory cells and cytokine milieu for autoregulative tumor growth signaling in pancreatic cancer. We analyzed the expression of TLR2, -4, and -9 in primary human cancers and their impact on tumor growth via induced activation in several established pancreatic cancers. TLR-stimulated pancreatic cancer cells were specifically investigated for activated signaling pathways of VEGF/PDGF and anti-apoptotic Bcl-xL expression as well as tumor cell growth. The primary pancreatic cancers and cell lines expressed TLR2, -4, and -9. TLR-specific stimulation resulted in activated MAP-kinase signaling, most likely via autoregulative stimulation of demonstrated TLR-induced VEGF and PDGF expression. Moreover, TLR activation prompted the expression of Bcl-xL and has been demonstrated for the first time to induce tumor cell proliferation in pancreatic cancer. These findings strongly suggest that pancreatic cancer cells use specific Toll like receptor signaling to promote tumor cell proliferation and emphasize the particular role of TLR2, -4, and -9 in this autoregulative process of tumor cell activation and proliferation in pancreatic cancer.

The clinical course of pulmonary embolism patients anticoagulated for 1 year: results of a prospective, observational, cohort study

BACKGROUND

Few studies have examined the clinical course of pulmonary embolism (PE) in patients anticoagulated continuously for 1 year.

OBJECTIVE

We sought to determine the incidence of death, recurrent PE and bleeding during anticoagulation in the first year after acute PE, and to assess associated risk factors.

METHODS

All consecutive PE patients who were referred to our center in Pisa, Italy between 2001 and 2005 received a conventional initial treatment, followed by vitamin K antagonists [international normalized ratio (INR), 2.0-3.0] for 1 year. They were followed-up at scheduled times at the study center. The development of recurrent PE was objectively documented and recorded.

RESULTS

Out of 497 patients, 48 (9.6%) developed recurrent PE, which was fatal in 36. Of these 48 events, 39 occurred within 10 days of diagnosis and only two patients had a non-fatal recurrent PE between 6 and 12 months. Risk factors associated with the risk for overall recurrent PE were persistent severe dyspnoea (P = 0.007), a high perfusion defect score index (PDI) (P = 0.003) and cardiopulmonary co-morbidities (P = 0.005). Unprovoked presentation (P = 0.030), persistent severe dyspnoea (P = 0.011) and a high PDI (P = 0.001) predicted the risk for fatal PE. Overall bleeding incidence was 3.4%, no cases of bleeding occurred between 180 and 360 days post-diagnosis.

CONCLUSIONS

In spite of conventional anticoagulation, a proportion of patients with PE experience both a fatal and non-fatal recurrent embolism within the first year. The large majority of these occur within the days proceeding diagnosis, with only a small minority occurring in the last 6 months. No bleeding was observed after 6 months. Therefore, prolonging anticoagulation for 1 year represents both a safe and effective treatment.

Analysis of polymorphism at site -174 G/C of interleukin-6 promoter region in multiple myeloma

It is well established that interleukin-6 (IL-6) is an essential growth factor for multiple myeloma (MM) and patients with increased IL-6 levels have a poor prognosis. In healthy subjects, the presence of the C allele at a polymorphic site (-174 G/C) of the IL-6 gene is related to low IL-6 levels. In view of the potential association of this particular polymorphism with IL-6 concentration, and the relevance of IL-6 in MM pathogenesis, the objective of the present study was to investigate the prevalence of IL-6 (-174 G/C) promoter polymorphism and its association with development of MM in Brazilian individuals. We investigated the prevalence of these alleles in 52 patients and 60 healthy subjects (matched by age, sex, and race) of a Brazilian population. Thirty patients were male (42.4%), 24 (46.2%) were white and the median age at diagnosis was 58.5 years (range: 28 to 84 years). To determine the IL-6 (-174 G/C) polymorphism, molecular analysis was performed by polymerase chain reaction followed by endonuclease restriction digestion. The genotype distributions observed in the group of patients were 4% CC, 42% GC and 54% GG. The C allele frequency was 0.25. These results were similar to the control group, suggesting no impact of this polymorphism on the susceptibility to MM.

Comparative analysis of predictive biomarkers for therapeutical strategies in colorectal cancer

BACKGROUND

Prognostic information regarding the risk of postoperative tumor recurrence defined by a profile of serological, morphological and/or molecular markers can have potential value, particularly for patients with colorectal carcinoma (CRC) of the International Union Against Cancer (UICC) stage II/III who may benefit from adjuvant chemotherapy after surgery.

METHODS

A retrospective study of 783 patients with CRC (UICC I-III) including a subgroup analysis of 116 subjects was conducted to determine preoperative serum carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 19-9, and p53 serum levels. In addition, protein and gene expression of p53, CEA, and adenomatous polyposis coli (APC) was assessed in the tumors of those patients. The values of all serological, morphological, and molecular parameters were correlated with clinicopathological characteristics for their predictive value of tumor recurrence over a mean follow-up period of 32 +/- 6.2 months.

RESULTS

Serum CEA but not CA 19-9 or p53 was a significant prognostic factor for disease-free survival, along with UICC and T/N stage. When comparing elevated CEA, CA 19-9, and p53 serum levels with expression of the markers in the tumors, their overall expression was found to be 61.3% in the serum versus 93.5% in the tumor in analyzed patients (n = 116). In particular, all patients in UICC stages I-III who demonstrated at least three elevated markers (CEA/CA 19-9/p53) in serum and/or in the tumor presented with tumor recurrence/metastases.

CONCLUSION

Overall increased p53, CEA, and CA 19-9 serum levels and their marker expression in the tumor may be used at the time of primary tumor removal for defining patients at risk for tumor recurrence.

Hydrogen peroxide impairs GRK2 translation via a calpain-dependent and cdk1-mediated pathway

Oxidative mechanisms of injury are involved in many neurodegenerative diseases such as stroke, ischemia-reperfusion injury and multiple sclerosis. G protein-coupled receptor kinase 2 (GRK2) plays a key role in G protein-coupled receptor (GPCR) signaling modulation, and its expression levels are decreased after brain hypoxia/ischemia and reperfusion as well as in several inflammatory conditions. We report here that hydrogen peroxide downregulates GRK2 expression in C6 rat glioma cells. The hydrogen peroxide-induced decrease in GRK2 is prevented by a calpain protease inhibitor, but does not involve increased GRK2 degradation or changes in GRK2 mRNA level. Instead we show that hydrogen peroxide treatment impairs GRK2 translation in a process that requires Cdk1 activation and involves the mTOR pathway. This novel mechanism for the control of GRK2 expression in glial cells upon oxidative stress challenge may contribute to the modulation of GPCR signaling in different pathological conditions.

Plasmablastic multiple myeloma is associated with increased vascular endothelial growth factor immunoexpression

The biologic basis of the negative prognosis of plasmablastic myeloma is not fully understood. To determine whether histologically aggressive multiple myeloma (MM) is associated with a more angiogenic marrow environment, bone marrow samples from 50 recently diagnosed MM patients were evaluated. Twelve percent (6/50) of patients presented plasmablastic MM, and this feature correlated with moderate/strong intensity of vascular endothelial growth factor staining of plasma cells (P = 0.036). Although plasmablastic MM was not associated with increasing of microvessel density, this new evidence of increased expression of vascular endothelial growth factor on plasmablasts suggests that the adverse prognosis conferred by plasmablastic disease may be due, at least in part, to secretion of this angiogenic cytokine, also suggesting that the subset of MM patients with plasmablastic features may derive particular benefit from antiangiogenic therapies.

Pubic bone anchoring devices for the surgical treatment of urinary stress incontinence in patients with severe genital prolapse

The aim of this study was to test a surgical technique for the treatment of stress urinary incontinence associated with genital prolapse through a transvaginal suspension anchored to the pubic bone. Thirty-seven patients with severe genital prolapse and urodynamically proven stress incontinence were operated on with this procedure from February 1998 to May 2000. Preoperatively a detailed history, pelvic examination and urodynamic studies were carried out. The degree of prolapse was assessed pre- and postoperatively in the lithotomy position in accordance with the classification proposed by Baden and Walker [8]. Two titanium bone screws with no. 1 polypropylene sutures attached to them and a battery-operated screw inserter are used to fix the vaginal sutures to the pubic bone bilaterally. The procedure is performed transvaginally with no abdominal or suprapubic incisions. Objective outcomes were assessed by symptom assessment, clinical examination and a full urodynamic evaluation at 6 months postoperatively, and annually by clinical evaluation. Subjective outcomes were assessed by directly interviewing the patients about their postoperative urinary symptoms and asking them to classify their level of satisfaction. An objective cure rate (no objective loss of urine during coughing in the absence of a simultaneous detrusor contraction) at the 6-month postoperative urodynamic evaluation was observed in 23 of 37 patients (62%). Recurrent anterior vaginal wall prolapse (grade 2) had developed in 7 of 37 patients (27%). Subjectively, 73% of the patients expressed satisfaction with the procedure. Early results using two bone screws into the pubis to fix the periurethral and perivesical tissues and vagina to the posterior surface of the pubic bone were disappointing. Based on our results we have abandoned the use of this procedure to correct stress incontinence associated with severe genital prolapse.

Brain alpha(2)-adrenoceptors in monoamine-depleted rats: increased receptor density, G coupling proteins, receptor turnover and receptor mRNA

1. This study was designed to assess the molecular and cellular events involved in the up-regulation (and receptor supersensitivity) of brain alpha(2)-adrenoceptors as a result of chronic depletion of noradrenaline (and other monoamines) by reserpine. 2. Chronic reserpine (0.25 mg kg(-1) s.c., every 48 h for 6 - 14 days) increased significantly the density (B(max) values) of cortical alpha(2)-adrenoceptor agonist sites (34 - 48% for [(3)H]-UK14304, 22 - 32% for [(3)H]-clonidine) but not that of antagonist sites (11 - 18% for [(3)H]-RX821002). Competition of [(3)H]-RX821002 binding by (-)-adrenaline further indicated that chronic reserpine was associated with up-regulation of the high-affinity state of alpha(2)-adrenoceptors. 3. In cortical membranes of reserpine-treated rats (0.25 mg kg(-1) s.c., every 48 h for 20 days), the immunoreactivities of various G proteins (Galphai(1/2), Galphai(3), Galphao and Galphas) were increased (25 - 34%). Because the high-affinity conformation of the alpha(2)-adrenoceptor is most probably related to the complex with Galphai(2) proteins, these results suggested an increase in signal transduction through alpha(2)-adrenoceptors (and other monoamine receptors) induced by chronic reserpine. 4. After alpha(2)-adrenoceptor alkylation, the analysis of receptor recovery (B(max) for [(3)H]-UK14304) indicated that the increased density of cortical alpha(2)-adrenoceptors in reserpine-treated rats was probably due to a higher appearance rate constant of the receptor ((Delta)r=57%) and not to a decreased disappearance rate constant ((Delta)k=7%). 5. Northern- and dot-blot analyses of RNA extracted from the cerebral cortex of saline- and reserpine-treated rats (0.25 mg kg(-1), s.c., every 48 h for 20 days) revealed that reserpine markedly increased the expression of alpha(2a)-adrenoceptor mRNA in the brain (125%). This transcriptional activation of the receptor gene expression appears to be the cellular mechanism by which reserpine induces up-regulation in the density of brain alpha(2)-adrenoceptors.

Chronic clorgyline induces selective down-regulation of alpha2-adrenoceptor agonist binding sites in rat brain

Inactivation of alpha2-adrenoceptors by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) has been shown to induce an increase in brain regulatory G alpha(i1/2) proteins, which was related to biphasic recovery of agonist binding sites. To investigate further the nature of this phenomenon, the chronic effects of clorgyline (a monoamine oxidase inhibitor antidepressant) on the recovery of alpha2-adrenoceptors after EEDQ and on EEDQ-induced up-regulation of G alpha(i1/2) proteins were assessed in rat brain. Clorgyline (1 mg kg(-1) for 7-35 days) induced a time-dependent down-regulation (20% to 55%) of the density of cortical alpha2-adrenoceptor agonist sites ([3H]UK 14304/bromoxidine binding) but not of antagonist sites ([3H]RX 821002/2-methoxy idazoxan binding). However, chronic clorgyline did not alter the immunoreactive levels of G alpha(i1/2), G alpha(i3), and G alpha(o) proteins in cortex. In clorgyline-treated rats, the turnover functions for agonist and antagonist binding sites (receptor recovery after EEDQ) were different and indicated that the reduced density of alpha2-adrenoceptor agonist sites induced by clorgyline was due to a greater rate of receptor disappearance. The recovery of [3H]UK 14304 binding in clorgyline-treated rats did not fit a biphasic recovery model and the turnover parameters were very similar to those obtained for the second phase of recovery (biphasic model) of agonist binding sites in naive rats. This suggested that clorgyline down-regulated only the alpha2-adrenoceptors of rapid turnover which is associated with the increases in the expression of G alpha(i1/2) proteins induced by EEDQ. In this context, clorgyline (1 mg kg(-1) for 7 days) fully prevented the up-regulation (50%) of brain G alpha(i1/2) proteins induced by EEDQ. The results indicate that one relevant mechanism involved in the in vivo desensitization of brain alpha2-adrenoceptors is an effective impairment of receptor-G protein coupling.

Activation of heterotrimeric G-protein signaling by a ras-related protein. Implications for signal integration

Utilizing a functional screen in the yeast Saccharomyces cerevisiae we identified mammalian proteins that activate heterotrimeric G-protein signaling pathways in a receptor-independent fashion. One of the identified activators, termed AGS1 (for activator of G-protein signaling), is a human Ras-related G-protein that defines a distinct subgroup of the Ras superfamily. Expression of AGS1 in yeast and in mammalian cells results in specific activation of Galpha(i)/Galpha(o) heterotrimeric signaling pathways. In addition, the in vivo and in vitro properties of AGS1 are consistent with it functioning as a direct guanine nucleotide exchange factor for Galpha(i)/Galpha(o). AGS1 thus presents a unique mechanism for signal integration via heterotrimeric G-protein signaling pathways.

[News about cancer in the press]

BACKGROUND

News on health and health care are increasingly common in the mass media, and cancer is one of the most prominent topic among these news due to its health impact.

MATERIAL AND METHODS

All news published in major newspapers in Catalonia, Spain between April to December 1996 were analysed, together with items from science and health supplements general information and science journals. Types of cancer-related topics, sources of information, the importance of cancer in the news item and the theme of the piece were analysed.

RESULTS

During the period analysed, 974 news items were published which dealt with cancer. Of these, cancer was the principal topic in 53.5% of the items published in the national press, and 63.4% of the items published in the regional press. Cancer was the subject of an editorial comment on only four occasions. The source of information was mentioned in 64.8% of the items, and mean number of sources was 1.6. Political institutions were the most frequent source of information in newspapers, while science and health supplements and other magazines tended to cite scientific and health care institutions, as well as scientific journals. Basic research was the most common topic for news (30.3%) in science and health supplements while risk and environmental factors (29.6%) were the most common topics in magazines; environmental and technological risk factors (18,6%) and conflicts with health administrative bodies (16%) were the most frequent topics in the newspapers.

CONCLUSION

News about risk factors and their prevention as well as technological and environmental factors related to cancer were among the most important topics published in the general press and magazines, together with conflicts with administrative bodies. Informations related to new therapies were a less frequent topic. Scientific journals have an important role as an information source for mass media together with political and scientific institutions.

Receptor-independent activators of heterotrimeric G-protein signaling pathways

Heterotrimeric G-protein signaling systems are activated via cell surface receptors possessing the seven-membrane span motif. Several observations suggest the existence of other modes of stimulus input to heterotrimeric G-proteins. As part of an overall effort to identify such proteins we developed a functional screen based upon the pheromone response pathway in Saccharomyces cerevisiae. We identified two mammalian proteins, AGS2 and AGS3 (activators of G-protein signaling), that activated the pheromone response pathway at the level of heterotrimeric G-proteins in the absence of a typical receptor. beta-galactosidase reporter assays in yeast strains expressing different Galpha subunits (Gpa1, G(s)alpha, G(i)alpha(2(Gpa1(1-41))), G(i)alpha(3(Gpa1(1-41))), Galpha(16(Gpa1(1-41)))) indicated that AGS proteins selectively activated G-protein heterotrimers. AGS3 was only active in the G(i)alpha(2) and G(i)alpha(3) genetic backgrounds, whereas AGS2 was active in each of the genetic backgrounds except Gpa1. In protein interaction studies, AGS2 selectively associated with Gbetagamma, whereas AGS3 bound Galpha and exhibited a preference for GalphaGDP versus GalphaGTPgammaS. Subsequent studies indicated that the mechanisms of G-protein activation by AGS2 and AGS3 were distinct from that of a typical G-protein-coupled receptor. AGS proteins provide unexpected mechanisms for input to heterotrimeric G-protein signaling pathways. AGS2 and AGS3 may also serve as novel binding partners for Galpha and Gbetagamma that allow the subunits to subserve functions that do not require initial heterotrimer formation.

Press releases of science journal articles and subsequent newspaper stories on the same topic

CONTEXT

Scientific journals issue press releases to disseminate scientific news about articles they publish.

OBJECTIVE

To assess whether press releases about journal articles were associated with publication of subsequent newspaper stories.

DESIGN

Retrospective content analysis of newspaper stories, journal press releases, and journal tables of contents. From December 1, 1996, to February 28, 1997, press releases and tables of contents were collected from BMJ, Nature, Science, and The Lancet, along with newspaper stories on scientific research published in The New York Times (United States), Le Figaro and Le Monde (France), El País and La Vanguardia (Spain), La Repubblica (Italy), and the International Herald Tribune.

MAIN OUTCOME MEASUREMENTS

Number of newspaper stories that contained reference to articles appearing in the 4 scientific journals, number of newspaper stories that referred to journal articles described in press releases, and the order in which journal articles were mentioned in press releases.

RESULTS

Of the 1060 newspaper stories analyzed, 142 referred to journal articles; of these, 119 (84%) referred to articles mentioned in press releases and 23 (16%) referred to journal articles not mentioned in press releases (comparison of proportions, P=.03). Articles described first or second were referenced in more newspapers than articles described later in the press release (P=.01 by chi2 analysis).

CONCLUSIONS

Journal articles described in press releases, in particular those described first or second in the press release, are associated with the subsequent publication of newspaper stories on the same topic.

Effects of the alkylating agent EEDQ on regulatory G proteins and recovery of agonist and antagonist alpha2-adrenoceptor binding sites in rat brain

The aim of this study was to assess the effect of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ)-induced alpha2-adrenoceptor inactivation on regulatory G proteins and the recovery of agonist and antagonist binding sites. EEDQ induced a rapid increase in the abundance of rat brain cortical Galphai1/2 proteins (30% at 6 h) which reached a maximum at 4 days (45%) and which then slowly returned (7-30 days) to control values. EEDQ did not alter significantly the levels of Galphai3 and Galphao proteins. By using the standard monoexponential model, the analysis of the recovery of alpha2-adrenoceptor density (6 h-30 days) with [3H]UK 14304 (bromoxidine) and [3H]RX 821002 (2-metoxy idazoxan) in the cerebral cortex did not reveal differences in receptor turnover parameters. However, the recovery of [3H]UK 14304 binding fitted best to a new biphasic recovery model, suggesting the existence of two distinct phases of recovery of agonist sites (r1 and r2 = 15.7 and 7.4 fmol mg protein(-1) day(-1); k1 and k2 = 0.51 and 0.25 day(-1); (t1/2)1 and (t1/2)2 = 1.4 and 2.7 days). In contrast, the recovery of [3H]RX 821002 antagonist sites did not fit to the biphasic model (r = 8.1, k = 0.14, t1/2 = 4.9). Because agonist binding requires coupling to G proteins, the present results suggest that the rapid over-expression of Galphai1/2 proteins induced by EEDQ is related to the biphasic recovery of [3H]UK 14304 binding. The possible implication of the faster recovery of alpha2-adrenoceptor function after EEDQ inactivation is discussed.

Role of lipid polymorphism in G protein-membrane interactions: nonlamellar-prone phospholipids and peripheral protein binding to membranes

Heterotrimeric G proteins (peripheral proteins) conduct signals from membrane receptors (integral proteins) to regulatory proteins localized to various cellular compartments. They are in excess over any G protein-coupled receptor type on the cell membrane, which is necessary for signal amplification. These facts account for the large number of G protein molecules bound to membrane lipids. Thus, the protein-lipid interactions are crucial for their cellular localization, and consequently for signal transduction. In this work, the binding of G protein subunits to model membranes (liposomes), formed with defined membrane lipids, has been studied. It is shown that although G protein alpha-subunits were able to bind to lipid bilayers, the presence of nonlamellar-prone phospholipids (phosphatidylethanolamines) enhanced their binding to model membranes. This mechanism also appears to be used by other (structurally and functionally unrelated) peripheral proteins, such as protein kinase C and the insect protein apolipophorin III, indicating that it could constitute a general mode of protein-lipid interactions, relevant in the activity and translocation of some peripheral (amphitropic) proteins from soluble to particulate compartments. Other factors, such as the presence of cholesterol or the vesicle surface charge, also modulated the binding of the G protein subunits to lipid bilayers. Conversely, the binding of G protein-coupled receptor kinase 2 and the G protein beta-subunit to liposomes was not increased by hexagonally prone lipids. Their distinct interactions with membrane lipids may, in part, explain the different cellular localizations of all of these proteins during the signaling process.

Characterization of a G-protein activator in the neuroblastoma-glioma cell hybrid NG108-15

Purified bovine brain G-protein was used in a solution phase assay to identify membrane-associated proteins that influenced the activation of heterotrimeric G-proteins. Detergent-solubilized membrane extracts from the neuroblastoma-glioma cell hybrid NG108-15, but not the parent C6B4 glioma cell line, increased [35S]GTPgammaS binding to purified G-protein by approximately 460%. The G-protein activator was heat-sensitive, and the magnitude of its action was related to the amount of extract protein. The biophysical and biochemical properties of the G-protein activator were determined using DEAE ion exchange chromatography, gel filtration, and a lectin affinity matrix. In the presence of added GDP (1 microM), the enriched G-protein activator increased the initial rate of [35S]GTPgammaS binding to brain G-protein by up to 4-fold. In the absence of added GDP, the G-protein activator elicited an initial burst in [35S]GTPgammaS binding to brain G-protein within the first 30 s, after which the rate of nucleotide binding to G-protein was similar in the absence or presence of the G-protein activator. The stimulation of nucleotide binding to brain G-protein by the activator was also observed after resolution of Galpha from Gbetagamma. The G-protein activator was distinct from other proteins (neuromodulin, tubulin, and beta-amyloid precursor protein) that influence nucleotide binding to G-protein, indicating the existence of a novel signal accelerator.

Vaginal hysterectomy with the Autosuture stapler

Our objective was to assess the applicability of hysterectomy by the vaginal route completely performed with Autosuture staples. Between January 1992 and September 1993, 5 vaginal hysterectomies using Autosuture staplers were performed by the authors. Five vaginal hysterectomies matched for age, parity, and uterine size performed by the same surgeons using reabsorbable sutures during the same period were used as case controls. No febrile morbidity, cuff infections, thrombophlebitis, bladder injury, or hemorrhage complications were observed in the 10 women who entered the study. In summary, vaginal hysterectomy can be performed with Autosutures easily, probably faster with experience, and with less oozing from the operative field, thus providing a safe procedure.

Differential effects of the alkylating agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline on brain alpha 2-adrenoceptors and I2-imidazoline sites in vitro and in vivo

The alkylating agent N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) is a peptide-coupling agent that is being used to inactivate irreversibly alpha 2-adrenoceptors and other receptors. The aim of the present study was to assess the in vitro and in vivo effects of EEDQ on the newly discovered brain I2-imidazoline sites, located mainly in mitochondria. Preincubation of rat cortical membranes with EEDQ (10(-8)-10(-5) M) markedly decreased (20-90%) the specific binding of the selective antagonist [3H]RX821002 to alpha 2-adrenoceptors without affecting that of [3H]idazoxan (in the presence of adrenaline) to I2-imidazoline sites. In EEDQ-pretreated membranes (10(-5) M, 30 min at 25 degrees C), the density of I2-imidazoline sites (Bmax = 80 +/- 4 fmol/mg of protein) was not different from that determined in untreated membranes in the presence of (10(-6) M (-)-adrenaline (Bmax = 83 +/- 4 fmol/mg of protein), and both densities were lower (24%, p < 0.05) than the total native density of [3H]idazoxan binding sites (Bmax = 107 +/- 6 fmol/mg of protein) (I2-imidazoline sites plus alpha 2-adrenoceptors). Treatment of rats with an optimal dose of EEDQ (1.6 mg/kg, i.p., for 2 h to 30 days) reduced maximally at 6 h (by 95 +/- 1%) the specific binding of [3H]-RX821002 to alpha 2-adrenoceptors, but also the binding of [3H]idazoxan to I2-imidazoline sites (by 44 +/- 5%). Pretreatment with yohimbine (10 mg/kg, i.p.) fully protected against EEDQ-induced alpha 2-adrenoceptor inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

No effect of genetic obesity and mazindol on imidazoline I2 binding sites in the brain of Zucker rats

The density and affinity states of imidazoline I2 binding sites as well as the density of alpha 2-adrenoceptors were quantitated in the brain of lean and obese Zucker rats. No significant differences were obtained between Zucker phenotypes for these receptors in the cerebral cortex and hypothalamus. Moreover, chronic treatment with the anorexic imidazoline derivative, mazindol, did not alter the density of brain imidazoline I2 binding sites. It is concluded that this genetic model of obesity is not associated with abnormal imidazoline I2 binding sites.

Acceleration by chronic treatment with clorgyline of the turnover of brain alpha 2-adrenoceptors in normotensive but not in spontaneously hypertensive rats

1. The aim of this study was to quantitate and compare the turnover of alpha 2-adrenoceptors in the cerebral cortex of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats, and its modulation during chronic treatment with the monoamine oxidase (MAO) inhibitor, clorgyline. 2. In SHR, the specific binding of the agonist [3H]-UK 14304 and of the antagonist [3H]-RX 821002 was significantly reduced in the brain (Bmax 15-19% lower) as compared to that in sex- and age-matched WKY rats. In contrast, no significant changes in the Kd values for both radioligands were found between WKY and SHR rats. Therefore, SHR rats offer a genetic model with a lower density of alpha 2-adrenoceptors in the brain. 3. Chronic treatment (21-35 days) with clorgyline (1 mg kg-1, i.p.) markedly decreased the density of brain alpha 2-adrenoceptors ([3H]-UK 14304 binding) in Sprague-Dawley (Bmax reduced by 50%) and in WKY (Bmax reduced by 30%) rats without any apparent change in the affinity of the radioligand. In contrast, the density of brain alpha 2-adrenoceptors in SHR was not down-regulated by chronic clorgyline treatment. 4. The recovery of [3H]-UK 14304 binding after irreversible inactivation by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ; 1.6 mg kg-1) (an alkylating agent for the alpha 2-adrenoceptor) was assessed in control and clorgyline-treated (1 mg kg-1; i.p. for 7-21 days) WKY and SHR rats to study the process of alpha 2-adrenoceptor repopulation and to calculate receptor turnover parameters. 5. The simultaneous analysis of receptor recovery curves revealed that the turnover of brain alpha2-adrenoceptors in SHR rats was accelerated (k = 0.141 day-1;t 1/2= 4.9 days; r/k =40 fmol mg-1 protein)compared to that in WKY rats (k = 0.085 day-1; tl/2= 8.1 days; r/k = 54 fmol mg-1 protein) and that the reduced density of cortical alpha2-adrenoceptors (Bmax or r/k values) in SHR was probably due to an abnormal higher receptor degradation (delta k = 66%) and not to a decreased receptor synthesis which in fact showed a slight increase (delta r = 24%).6. Treatment with clorgyline (1 mg kg-1, i.p. for 21 days) accelerated the turnover of brain alpha2-adrenoceptors in WKY rats (k = 0.328 days-1; tl/2= 2.1 days; r/k = 29 fmol mg-1 protein) and the greater increase in receptor degradation (delta k = 286%) over receptor synthesis (delta r = 109%) led to down-regulation of receptor density (r/k = 46% lower). In contrast, treatment with clorgyline did not modify significantly the turnover of brain M2-adrenoceptors in SHR (k = 0.192 days-1; t1/2 = 3.6 days;r/k = 39 fmol mg-1 protein), indicating that in this genetic model of hypertension, the desensitized alpha2-adrenoceptors cannot be further down-regulated by clorgyline treatment and that they lack the expected adaptative increase in receptor synthesis.

Susceptibility of Enterococcus faecalis to twelve antibiotics, time-kill assays, and high-level aminoglycoside resistance in a university hospital in Argentina

A total of 201 Enterococcus faecalis strains isolated from different body sites were tested to (i) establish their antibiotic susceptibility pattern; (ii) determine the percentage of strains highly resistant (MIC greater than 2,000 micrograms/ml) to five aminoglycosides and (iii) know if the combination of penicillin or ampicillin plus an aminoglycoside is reliably synergistic for the strains with low-level resistance (MICs ranged from the break point of susceptibility for each aminoglycoside to 2,000 micrograms/ml). Erythromycin exhibited very poor activity with MIC90 greater than 128 micrograms/ml. Pefloxacin and norfloxacin had intermediate activity, inhibiting 50% of isolates at 4 micrograms/ml and 90% at 8 micrograms/ml. Trimethoprim-sulfamethoxazole (1:20) inhibited 94% of isolates at less than or equal to 2 micrograms/ml and 87.6% at less than or equal to 0.5 microgram/ml. Ampicillin, penicillin and piperacillin were the most potent agents studied. Ninety percent of strains were inhibited at 1 microgram/ml of ampicillin and 4 micrograms/ml of penicillin and piperacillin. The E. faecalis isolates were relatively or totally resistant to the aminoglycosides. Ninety six (47.8%) were highly resistant at least to one of them. High level resistance to streptomycin was found in 47.3% of all strains and was the most frequent resistance encountered; amikacin highly resistant strains were the less common and accounted for 4.5%. Low-level resistance to the aminoglycosides ranged from 50.2% (for streptomycin) to 94.5% (for amikacin). Thirty one E. faecalis isolates were selected for 24-time kill-assays. There was a good correlation between resistance to penicillin or ampicillin aminoglycoside synergy in all but 3 strains which were highly resistant. Among the strains with low-level resistance to the aminoglycosides, there was no synergy in 37 (63.8%) of 58 killing assays with each of the aminoglycosides combined with penicillin. These results demonstrate that the susceptibility to 2,000 micrograms/ml of the aminoglycoside does not assure the penicillin or ampicillin aminoglycoside synergism.

[First radiological description of Morgagni's hydatid. Laparoscopic confirmation]

The authors explain the clinical case of a female patient suffering from secondary sterility; she was submitted, among other test, to the H.S.G. in order to study the possibility of a among other tests, to the H.S.G. in order to study the possibility of a cervical failure. The radiological findings obtained of Morgagni's Hydatis, not described previously in literature and their laparoscopic confirmation justify, we believe, its publication.