Safety, acceptability, and feasibility of a single-visit approach to cervical-cancer prevention in rural Thailand: a demonstration project

BACKGROUND

To increase screening and treatment coverage, innovative approaches to cervical-cancer prevention are being investigated in rural Thailand. We assessed the value of a single-visit approach combining visual inspection of the cervix with acetic acid wash (VIA) and cryotherapy.

METHODS

12 trained nurses provided services in mobile (village health centre-based) and static (hospital-based) teams in four districts of Roi-et Province, Thailand. Over 7 months, 5999 women were tested by VIA. If they tested positive, after counselling about the benefits, potential risks, and probable side-effects they were offered cryotherapy. Data measuring safety, acceptability, feasibility, and effort to implement the programme were gathered.

FINDINGS

The VIA test-positive rate was 13.3% (798/5999), and 98.5% (609/618) of those eligible accepted immediate treatment. Overall, 756 women received cryotherapy, 629 (83.2%) of whom returned for their first follow-up visit. No major complications were recorded, and 33 (4.4%) of those treated returned for a perceived problem. Only 17 (2.2%) of the treated women needed clinical management other than reassurance about side-effects. Both VIA and cryotherapy were highly acceptable to the patients (over 95% expressed satisfaction with their experience). At their 1-year visit, the squamocolumnar junction was visible to the nurses, and the VIA test-negative rate was 94.3%.

INTERPRETATION

A single-visit approach with VIA and cryotherapy seems to be safe, acceptable, and feasible in rural Thailand, and is a potentially efficient method of cervical-cancer prevention in such settings.

Response of the timeless protein to light correlates with behavioral entrainment and suggests a nonvisual pathway for circadian photoreception

The period (per) and timeless (tim) genes are required for circadian behavioral rhythms in Drosophila. The current model for how these rhythms entrain to light is based upon the light induced decrease in timeless protein (TIM) levels. We show here that the TIM response to light correlates with the effect of light on the behavioral rhythm. To identify components of the entrainment pathway, we also assayed the TIM response in flies with mutant visual systems. Flies that lacked eyes displayed a normal response in lateral neurons. The TIM response to a light pulse was attenuated in flies that were mutant for the transient receptor potential (trp) and trp-like (trpl) genes, which are required for calcium conductance in the visual transduction cascade. The reduced TIM response was accompanied by a reduced phase shift in the behavioral rhythm, but neither response was completely eliminated, and the trpl;trp flies entrain to light-dark cycles, suggesting that these genes perturb some aspect of circadian entrainment when mutated but are not essential for it. The TIM response was also unaffected in ninaE flies that lack the rhodopsin protein (rh1). These results support the hypothesis that circadian entrainment does not rely on the visual system and likely involves a dedicated pathway for photoreception.

Enabled plays key roles in embryonic epithelial morphogenesis in Drosophila

Studies in cultured cells and in vitro have identified many actin regulators and begun to define their mechanisms of action. Among these are Enabled (Ena)/VASP proteins, anti-Capping proteins that influence fibroblast migration, growth cone motility, and keratinocyte cell adhesion in vitro. However, partially redundant family members in mammals and maternal Ena contribution in Drosophila previously prevented assessment of the roles of Ena/VASP proteins in embryonic morphogenesis in flies or mammals. We used several approaches to remove maternal and zygotic Ena function, allowing us to address this question. We found that inactivating Ena does not disrupt cell adhesion or epithelial organization, suggesting its role in these processes is cell type-specific. However, Ena plays an important role in many morphogenetic events, including germband retraction, segmental groove retraction and head involution, whereas it is dispensable for other morphogenetic movements. We focused on dorsal closure, analyzing mechanisms by which Ena acts. Ena modulates filopodial number and length, thus influencing the speed of epithelial zippering and the ability of cells to match with correct neighbors. We also explored filopodial regulation in cultured Drosophila cells and embryos. These data provide new insights into developmental and mechanistic roles of this important actin regulator.

The teacher as observer and experimenter in the modification of disputing and talking-out behaviors

Disputing and talking-out behaviors of individual pupils and entire classroom groups in special education classes and regular classes from white middle-class areas and from all black poverty areas ranging from the first grade to junior high school were studied. The classroom teacher in each case acted as the experimenter and as an observer. Various means of recording behaviors were used and reliability of observation was checked by an outside observer, another teacher, a teacher-aide, a student, or by using a tape recorder. Observation sessions varied from 15 min to an entire school day. After baseline rates were obtained, extinction of inappropriate disputing or talking-out behaviors and reinforcement of appropriate behavior with teacher attention, praise and in some cases a desired classroom activity or a surprise at the end of the week brought a decrease in undesired verbalizations. A reversal of contingencies brought a return to high levels of inappropriate talking with a return to low levels when reinforcement for appropriate talking was reinstated. The experiments demonstrated that teachers in a variety of classroom settings could obtain reliable observational records and carry out experimental manipulations successfully using resources available in most schools.

A Drosophila homolog of cyclase-associated proteins collaborates with the Abl tyrosine kinase to control midline axon pathfinding

We demonstrate that Drosophila capulet (capt), a homolog of the adenylyl cyclase-associated protein that binds and regulates actin in yeast, associates with Abl in Drosophila cells, suggesting a functional relationship in vivo. We find a robust and specific genetic interaction between capt and Abl at the midline choice point where the growth cone repellent Slit functions to restrict axon crossing. Genetic interactions between capt and slit support a model where Capt and Abl collaborate as part of the repellent response. Further support for this model is provided by genetic interactions that both capt and Abl display with multiple members of the Roundabout receptor family. These studies identify Capulet as part of an emerging pathway linking guidance signals to regulation of cytoskeletal dynamics and suggest that the Abl pathway mediates signals downstream of multiple Roundabout receptors.

Cervical cancer prevention: safety, acceptability, and feasibility of a single-visit approach in Accra, Ghana

OBJECTIVE

The purpose of this study was to assess the safety and acceptability of a single-visit approach to cervical cancer prevention combining visual inspection of the cervix with acetic acid wash (VIA) and cryotherapy.

STUDY DESIGN

The study was observational. Nine clinicians were trained in VIA and cryotherapy. Over 18 months 3665 women were VIA-tested. If positive and eligible, cryotherapy was offered immediately. Treated women were followed-up at 3 months and 1 year.

RESULTS

The test-positive rate was 13.2%. Of those eligible, 70.2% and 21% received immediate or delayed treatment, respectively. No major complications were recorded, and 5.6% presented for a perceived problem post-cryotherapy. Among those treated over 90% expressed satisfaction with their experience, and 96% had an indentifiable squamo-columnar junction. Only 2.6% (6/232) were test positive, 1-year posttreatment.

CONCLUSION

A single-visit approach using VIA and cryotherapy proved to be safe, acceptable, and feasible in an urban African setting.

Conserved regions of the timeless (tim) clock gene in Drosophila analyzed through phylogenetic and functional studies

Circadian (approximately 24-hr) rhythms in Drosophila melanogaster depend upon cyclic expression of the period (per) and timeless (tim) genes, which encode interacting components of the endogenous clock. The per gene has been isolated from other insects and, more recently, a per ortholog was found in mammals where its expression oscillates in a circadian fashion. We report here the complete sequence of a tim gene from another species, Drosophila virilis. TIM is better conserved than the PER protein is between these two species (76 vs. 54% overall amino acid identity), and putative functional domains, such as the PER interaction domains and the nuclear localization signal, are highly conserved. The acidic domain and the cytoplasmic localization domain, however, are within the least conserved regions. In addition, the initiating methionine in the D. virilis gene lies downstream of the proposed translation start for the original D. melanogaster tim cDNA and corresponds to the one used by D. simulans and D. yakuba. Among the most conserved parts of TIM is a region of unknown function near the N terminus. We show here that deletion of a 32 amino acid segment within this region affects rescue of rhythms in arrhythmic tim01 flies. Flies carrying a full-length tim transgene displayed rhythms with approximately 24-hr periods, indicating that a fully functional clock can be restored in tim01 flies through expression of a tim transgene. Deletion of the segment mentioned above resulted in very long activity rhythms with periods ranging from 30.5 to 48 hr.

Prevention of pulmonary thromboembolism by NCX 4016, a nitric oxide-releasing aspirin

We studied the antithrombotic activity of 2-acetoxybenzoate 2-[1-nitroxy-methyl]-phenyl ester (NCX 4016), a novel nitric oxide (NO)-releasing aspirin derivative, in vivo in different animal models of platelet-dependent and independent pulmonary thromboembolism and compared it with that of aspirin. NCX 4016 protected mice from death induced by the intravenous (i.v.) injection of collagen plus epinephrine, of 9,11-dideoxy-11alpha, 9alpha-epoxymethano-prostaglandin F(2alpha) (U46619) and of thrombin while aspirin was only active against collagen plus epinephrine. The drop in platelet count and number of lung emboli were reduced by NCX 4016 more effectively than aspirin. NCX 4016 protected mice also from mechanical pulmonary embolism (i.v. injection of hardened rat red blood cells) while aspirin was ineffective. In rabbits, NCX 4016 significantly reduced the accumulation of [111In]oxine-labeled platelets in the pulmonary vasculature induced by collagen and by thrombin while aspirin produced reductions which were significant only versus collagen. In conclusion, NCX 4016 exerts a more pronounced antithrombotic activity than aspirin in vivo in two different animal species, largely due to a deeper inhibitory effect on platelets. NCX 4016 may represent a better antithrombotic agent than aspirin.

Role of inorganic nitrate and nitrite in driving nitric oxide-cGMP-mediated inhibition of platelet aggregation in vitro and in vivo

BACKGROUND

Nitric oxide (NO) is a critical negative regulator of platelets that is implicated in the pathology of thrombotic diseases. Platelets generate NO, but the presence and functional significance of NO synthase (NOS) in platelets is unclear. Inorganic nitrate/nitrite is increasingly being recognized as a source of bioactive NO, although its role in modulating platelets during health and vascular dysfunction is incompletely understood.

METHODS

We investigated the functional significance and upstream sources of NO-cGMP signaling events in platelets by using established methods for assessing in vitro and in vivo platelet aggregation, and assessed the bioconversion of inorganic nitrate to nitrite during deficiency of endothelial NOS (eNOS).

RESULTS

The phosphodiesterase 5 (PDE5) inhibitor sildenafil inhibited human platelet aggregation in vitro. This inhibitory effect was abolished by a guanylyl cyclase inhibitor and NO scavengers, but unaffected by NOS inhibition. Inorganic nitrite drove cGMP-mediated inhibition of human platelet aggregation in vitro and nitrate inhibited platelet function in eNOS(-/-) mice in vivo in a model of thromboembolic radiolabeled platelet aggregation associated with an enhanced plasma nitrite concentration as compared with wild-type mice.

CONCLUSIONS

Platelets generate transient, endogenous cGMP signals downstream of NO that are primarily independent of NOS and may be enhanced by inhibition of PDE5. Furthermore, nitrite can generate transient NO-cGMP signals in platelets. The absence of eNOS leads to enhanced plasma nitrite levels following nitrate administration in vivo, which negatively impacts on platelet function. Our data suggest that inorganic nitrate exerts an antiplatelet effect during eNOS deficiency, and, potentially, that dietary nitrate may reduce platelet hyperactivity during endothelial dysfunction.

Platelet aggregation responses are critically regulated in vivo by endogenous nitric oxide but not by endothelial nitric oxide synthase

BACKGROUND AND PURPOSE

Although exogenous nitric oxide (NO) clearly modifies platelet function, the role and the source of endogenous NO in vivo remain undefined. In addition, endothelial NO synthase (NOS-3) critically regulates vessel tone but its role in modulating platelet function is unclear. In this paper we have investigated the roles of endogenous NO and NOS-3 in regulating platelet function in vivo and determined the functional contribution made by platelet-derived NO.

EXPERIMENTAL APPROACH

We used a mouse model for directly assessing platelet functional responses in situ in the presence of an intact vascular endothelium with supporting in vitro and molecular studies.

KEY RESULTS

Acute NOS inhibition by N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME) enhanced platelet aggregatory responses to thrombin and platelets were shown to be regulated primarily by NO sources external to the platelet. Elevation of endogenous NOS inhibitors to mimic effects reported in patients with cardiovascular diseases did not enhance platelet responses. Platelet responsiveness following agonist stimulation was not modified in male or female NOS-3(-/-) mice but responses in NOS-3(-/-) mice were enhanced by L-NAME.

CONCLUSIONS AND IMPLICATIONS

Platelets are regulated by endogenous NO in vivo, primarily by NO originating from the environment external to the platelet with a negligible or undetectable role of platelet-derived NO. Raised levels of endogenous NOS inhibitors, as reported in a range of diseases were not, in isolation, sufficient to enhance platelet activity and NOS-3 is not essential for normal platelet function in vivo due to the presence of bioactive NO following deletion of NOS-3.

Characterization and functional significance of calcium transients in the 2-cell mouse embryo induced by an autocrine growth factor

Growth of preimplantation embryos is influenced by autocrine trophic factors that need to act by the 2-cell stage, but their mode of action is not yet described. This report shows that late zygote and 2-cell stage mouse embryos responded to embryo-derived platelet-activating factor (PAF) with transient increases in intracellular calcium concentration ([Ca(2+)](i)). [Ca(2+)](i) transients were single global events and were specifically induced by embryo-derived PAF. They were blocked by inhibition of phospholipase C (U 73122) and an inositol trisphosphate (IP(3)) receptor antagonist (xestospongin C), indicating the release of calcium from IP(3)-sensitive intracellular stores. Transients were also inhibited by the absence of calcium from extracellular medium and partially inhibited by treatment with dihydropyridine (nifedipine, 10 micrometer), but not pimozide (an inhibitor of an embryonic T-type calcium channel). (+/-)BAY K8644 (an L-type channel agonist) induced [Ca(2+)](i) transients, yet these were completely inhibited by nifedipine (10 micrometer). The complete inhibition of BAY K8644, but only partial inhibition of PAF by nifedipine shows that L-type channels were only partly responsible for the calcium influx. Depolarization of 2-cell embryos by 50 mm K(+) did not inhibit PAF-induced calcium transients, showing that the influx channels were not voltage-dependent. Depletion of intracellular calcium stores by thapsigargin revealed the presence of store-operated channels. The interdependent requirement for IP(3)-sensitive internal calcium stores and extracellular calcium in the generation of PAF-induced transients may be explained by a requirement for capacitative calcium entry via store-operated channels. A functionally important role for the PAF-induced transients is supported by the observation that inhibition of [Ca(2+)](i) transients by a PAF-antagonist (WEB 2086) or an intracellular calcium chelator (1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis-acetoxymethyl ester; BAPTA-AM) caused marked inhibition of early embryo development. Growth inhibition by BAPTA-AM was relieved by addition of exogenous PAF.

Respondent-driven sampling for an adolescent health study in vulnerable urban settings: a multi-country study

The global adolescent population is larger than ever before and is rapidly urbanizing. Global surveillance systems to monitor youth health typically use household- and school-based recruitment methods. These systems risk not reaching the most marginalized youth made vulnerable by conditions of migration, civil conflict, and other forms of individual and structural vulnerability. We describe the methodology of the Well-Being of Adolescents in Vulnerable Environments survey, which used respondent-driven sampling (RDS) to recruit male and female youth aged 15-19 years and living in economically distressed urban settings in Baltimore, MD; Johannesburg, South Africa; Ibadan, Nigeria; New Delhi, India; and Shanghai, China (migrant youth only) for a cross-sectional study. We describe a shared recruitment and survey administration protocol across the five sites, present recruitment parameters, and illustrate challenges and necessary adaptations for use of RDS with youth in disadvantaged urban settings. We describe the reach of RDS into populations of youth who may be missed by traditional household- and school-based sampling. Across all sites, an estimated 9.6% were unstably housed; among those enrolled in school, absenteeism was pervasive with 29% having missed over 6 days of school in the past month. Overall findings confirm the feasibility, efficiency, and utility of RDS in quickly reaching diverse samples of youth, including those both in and out of school and those unstably housed, and provide direction for optimizing RDS methods with this population. In our rapidly urbanizing global landscape with an unprecedented youth population, RDS may serve as a valuable tool in complementing existing household- and school-based methods for health-related surveillance that can guide policy.

Retinal progenitor cells release extracellular vesicles containing developmental transcription factors, microRNA and membrane proteins

A range of cell types, including embryonic stem cells, neurons and astrocytes have been shown to release extracellular vesicles (EVs) containing molecular cargo. Across cell types, EVs facilitate transfer of mRNA, microRNA and proteins between cells. Here we describe the release kinetics and content of EVs from mouse retinal progenitor cells (mRPCs). Interestingly, mRPC derived EVs contain mRNA, miRNA and proteins associated with multipotency and retinal development. Transcripts enclosed in mRPC EVs, include the transcription factors Pax6, Hes1, and Sox2, a mitotic chromosome stabilizer Ki67, and the neural intermediate filaments Nestin and GFAP. Proteomic analysis of EV content revealed retinogenic growth factors and morphogen proteins. mRPC EVs were shown to transfer GFP mRNA between cell populations. Finally, analysis of EV mediated functional cargo delivery, using the Cre-loxP recombination system, revealed transfer and uptake of Cre+ EVs, which were then internalized by target mRPCs activating responder loxP GFP expression. In summary, the data supports a paradigm of EV genetic material encapsulation and transfer within RPC populations. RPC EV transfer may influence recipient RPC transcriptional and post-transcriptional regulation, representing a novel mechanism of differentiation and fate determination during retinal development.

Influence of inflammation and nitric oxide upon platelet aggregation following deposition of diesel exhaust particles in the airways

Background and Purpose

Exposure to nanoparticulate pollution has been implicated in platelet‐driven thrombotic events such as myocardial infarction. Inflammation and impairment of NO bioavailability have been proposed as potential causative mechanisms. It is unclear, however, whether airways exposure to combustion‐derived nanoparticles such as diesel exhaust particles (DEP) or carbon black (CB) can augment platelet aggregation in vivo and the underlying mechanisms remain undefined. We aimed to investigate the effects of acute lung exposure to DEP and CB on platelet activation and the associated role of inflammation and endothelial‐derived NO.

Experimental Approach

DEP and CB were intratracheally instilled into wild‐type (WT) and eNOS^−/− mice and platelet aggregation was assessed in vivo using an established model of radio‐labelled platelet thromboembolism. The underlying mechanisms were investigated by measuring inflammatory markers, NO metabolites and light transmission aggregometry.

Key Results

Platelet aggregation in vivo was significantly enhanced in WT and eNOS^−/− mice following acute airways exposure to DEP but not CB. CB exposure, but not DEP, was associated with significant increases in pulmonary neutrophils and IL‐6 levels in the bronchoalveolar lavage fluid and plasma of WT mice. Neither DEP nor CB affected plasma nitrate/nitrite concentration and DEP‐induced human platelet aggregation was inhibited by an NO donor.

Conclusions and Implications

Pulmonary exposure to DEP and subsequent platelet activation may contribute to the reports of increased cardiovascular risk, associated with exposure to airborne pollution, independent of its effects on inflammation or NO bioavailability.

Integrin-linked kinase regulates the rate of platelet activation and is essential for the formation of stable thrombi

BACKGROUND

Integrin-linked kinase (ILK) and its associated complex of proteins are involved in many cellular activation processes, including cell adhesion and integrin signaling. We have previously demonstrated that mice with induced platelet ILK deficiency show reduced platelet activation and aggregation, but only a minor bleeding defect. Here, we explore this apparent disparity between the cellular and hemostatic phenotypes.

METHODS

The impact of ILK inhibition on integrin αII b β3 activation and degranulation was assessed with the ILK-specific inhibitor QLT0267, and a conditional ILK-deficient mouse model was used to assess the impact of ILK deficiency on in vivo platelet aggregation and thrombus formation.

RESULTS

Inhibition of ILK reduced the rate of both fibrinogen binding and α-granule secretion, but was accompanied by only a moderate reduction in the maximum extent of platelet activation or aggregation in vitro. The reduction in the rate of fibrinogen binding occurred prior to degranulation or translocation of αII b β3 to the platelet surface. The change in the rate of platelet activation in the absence of functional ILK led to a reduction in platelet aggregation in vivo, but did not change the size of thrombi formed following laser injury of the cremaster arteriole wall in ILK-deficient mice. It did, however, result in a marked decrease in the stability of thrombi formed in ILK-deficient mice.

CONCLUSION

Taken together, the findings of this study indicate that, although ILK is not essential for platelet activation, it plays a critical role in facilitating rapid platelet activation, which is essential for stable thrombus formation.

Induction of platelet aggregation after a direct physical interaction with diesel exhaust particles

BACKGROUND

There is a proven link between exposure to traffic-derived particulate air pollution and the incidence of platelet-driven cardiovascular diseases. It is suggested that inhalation of small, nanosized particles increases cardiovascular risk via toxicological and inflammatory processes and translocation of nanoparticles into the bloodstream has been shown in experimental models. We therefore investigated the ability of diesel exhaust particles (DEP) to interact physically and functionally with platelets.

METHODS

The interaction of DEP and carbon black (CB) with platelets was examined by transmission electron microscopy (TEM), whereas the functional consequences of exposure were assessed by measuring in vitro and in vivo platelet aggregation via established methods.

RESULTS

Both DEP and CB were internalized and seen in proximity with the open canalicular system in platelets. DEP induced platelet aggregation in vitro whereas CB had no effect. DEP induced Ca(2+) release, dense granule secretion and surface P-selectin expression, but not toxicologic membrane disruption. Low concentrations of DEP potentiated agonist-induced platelet aggregation in vitro and in vivo.

CONCLUSIONS

DEP associate physically with platelets in parallel with a Ca(2+) -mediated aggregation response displaying the conventional features of agonist-induced aggregation. The ability of DEP to enhance the aggregation response to platelet stimuli would be expected to increase the incidence of platelet-driven cardiovascular events should they be inhaled and translocate into the blood. This study provides a potential mechanism for the increased thrombotic risk associated with exposure to ambient particulate air pollution.

The plasma membrane calcium ATPase modulates calcium homeostasis, intracellular signaling events and function in platelets

BACKGROUND

The plasma membrane calcium ATPase (PMCA) regulates localized signaling events in a variety of cell types, although its functional role in platelets remains undefined.

OBJECTIVES

To investigate the role of PMCA in determining platelet intracellular calcium concentration ([Ca²(+) ](i) ) at rest and following agonist stimulation, and to define the corresponding effects upon different stages of platelet activation.

METHODS

[Ca²(+) ](i) was continuously measured in Fura-2-loaded platelets and in vitro and in vivo functional analyses performed in the presence of the PMCA inhibitor carboxyeosin (CE).

RESULTS

Concentrations of CE that selectively inhibited Ca²(+) extrusion through PMCA were established in human platelets. [Ca²(+) ](i) was elevated by CE in resting platelets, although collagen-stimulated Ca²(+) release was reduced. Impaired Ca²(+) mobilization upon agonist stimulation was accompanied by reduced dense granule secretion and impaired platelet aggregation. Platelet aggregation responses were also reduced in PMCA4(-/-) mice and in an in vivo mouse model of platelet thromboembolism. Conversely, inhibition of PMCA promoted the early and later stages of platelet activation, observed as enhanced adhesion to fibrinogen, and accelerated clot retraction. Investigations into the signaling mechanisms underlying CE-mediated inhibition of platelet aggregation implicated cGMP-independent vasodilator-stimulated phosphoprotein phosphorylation.

CONCLUSIONS

Disruption of PMCA activity perturbs platelet Ca²(+) homeostasis and function in a time-dependent manner, demonstrating that PMCA differentially regulates Ca²(+) -dependent signaling events, and hence function, throughout the platelet activation process.

Vasodilators and primary pulmonary hypertension. Variability of long-term response

Long-term response to vasodilator therapy was assessed in six patients with PPH. Following an acute trial, each patient was restudied after (1) two months of drug administration, (2) one month of abstinence from therapy, and (3) an additional two months of therapy. Three of six patients had no long-term reduction of PVR after treatment; one showed a progressive increase. Of the three patients whose PVR was still reduced at the end of the second therapy period none showed a return of PVR to baseline during the abstinence phase, which may suggest that long-term reduction of pulmonary vascular tone may modify the vasoconstrictive component of this disease. The heterogeneous response of this small number of patients to sequential drug administration and withdrawal demonstrates the difficulty of interpreting previously reported clinical trials and underscores the need for a well-designed controlled study of vasodilator administration in these patients.

Genomic structure, chromosomal location, and mutation analysis of the human CDC14A gene

Human CDC14A is a dual-specificity phosphatase that shares sequence similarity with the recently identified tumor suppressor, MMAC1/PTEN/TEP1. By radiation hybrid mapping, we localized CDC14A to chromosome band 1p21, a region that has been shown to exhibit loss of heterozygosity in highly differentiated breast carcinoma and malignant mesothelioma. We have mapped the exon-intron structure of CDC14A gene and found an in-frame ATG at 14 codons upstream of the previously reported start site (GenBank Accession No. AF000367). In screening a panel of 136 cDNAs from tumor cell lines for coding mutations, we have identified a 48-bp in-frame deletion in the cDNA of the breast carcinoma cell line, MDA-MB-436. This deletion is the result of an acceptor splice site mutation (AG to AT) in intron 12 that causes the skipping of exon 13 in the gene. Loss of expression of the wildtype allele in the same breast cell line supports the possibility that CDC14A may be a tumor suppressor gene that is targeted for inactivation during tumorigenesis.

Effects of dopamine and selective dopamine agonists upon platelet accumulation in the cerebral and pulmonary vasculature of the rabbit

1. A selection of novel compounds were shown to exhibit dopaminergic activity in vitro. 2. 111Indium-labelled platelets were continuously monitored in the cerebral and pulmonary vasculature of anaesthetized rabbits. The effects of dopamine and selective dopamine receptor agonists on ADP and thrombin induced platelet accumulation were recorded. 3. Pretreatment with dopamine (2 mg kg(-1) min(-1), i.v.) significantly reduced ADP (20 microg kg(-1), i.v.) induced platelet accumulation in the pulmonary vasculature whereas lower doses had no effect. 4. Dopamine (100 microg kg(-1) min(-1) intra-carotid, i.c.) potentiated thrombin (90 u kg(-1), i.c.) induced platelet accumulation in the cerebral vasculature whereas higher doses (1-2 mg kg(-1) min[-1]) inhibited accumulation. 5. The selective dopamine receptor agonists tested did not significantly inhibit platelet accumulation induced by ADP or thrombin. Two of these selective agonists, at doses higher than the intended therapeutic doses, induced thrombocytopaenia and an associated increase in platelet accumulation in the lung in response to thrombin. 6. These results extend previous in vitro studies regarding the dual actions of dopamine upon platelets and show for the first time the effects of selective dopamine receptor agonists upon platelet aggregation in vivo.

Thrombin inhibitors and anti-coagulants on thrombin-induced embolisation in rabbit cranial vasculature

111Indium-labelled platelets were continuously monitored in the cranial vasculature of anaesthetised rabbits and thrombin inhibitors and anti-coagulants were tested on the sustained platelet accumulation induced by intracarotid injection of thrombin (90 U/kg). Pretreatment, commencing 30 min prior to thrombin, with a 1-h intracarotid infusion of D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK; 0.25-1.0 micrograms/kg per min), unfractionated heparin (Multiparin; 5-20 U/kg bolus + 0.75-3.0 U/kg per min infusion) or low molecular weight heparin (Fragmin; 2.4-9.6 U/kg per min) produced dose-related reductions in platelet accumulation. Continuous infusion of acetyl-D-phenylalanyl-prolyl-boroarginine (DuP-714 ester; 30 micrograms/kg per min) for 30 min induced marked accumulation of platelets in the pulmonary circulation in the absence of thrombin. Bolus intracarotid injection, 1 min before thrombin, of Hirulog (0.05-0.2 mg/kg), PPACK (10-30 micrograms/kg), Multiparin (25-100 U/kg), Fragmin (150 U/kg) or DuP-714 ester (15-30 micrograms/kg) caused significant reductions in platelet accumulation. When injected 1 min after thrombin, Hirulog (1 mg/kg), PPACK (100 micrograms/kg), Fragmin (150 U/kg) and DuP-714 ester (30 micrograms/kg) had no significant effect and Multiparin (100 U/kg) increased platelet accumulation. The results demonstrate that pretreatment with a range of thrombin inactivators, acting via different mechanisms, can inhibit thrombin-induced cerebral thromboembolism in the rabbit.

Union status and sexual risk behavior among men in their 30s

CONTEXT

Understanding the relationship between union status and men's sexual risk behavior in their 30s is important to ensure appropriate reproductive health services for men in middle adulthood.

METHODS

Data from 1,083 men aged 34-41 who participated in the 2008-2010 wave of the National Survey of Adolescent Males were used to examine differentials in sexual risk behaviors by union status, past risk behavior and selected characteristics. Bivariate tabulations were done to assess relationships between current risk behavior and background variables, multinomial regression analysis was conducted to identify associations between union status and past risk behavior, and logistic regression analysis was used to assess associations between current behavior and both union status and past behavior.

RESULTS

Eight percent of men in their 30s had had three or more sexual partners in the last 12 months, 10% had had at least one risky partner and 8% had had concurrent partners. Men living outside co-residential unions reported higher levels of these behaviors (24%, 29% and 24%, respectively) than did married men (1-2%) or cohabiting men (7-12%). In multivariate analyses that controlled for past risk behavior, married men were less likely than cohabiting men to have had at least one risky partner or concurrent partners in the last year (odds ratio, 0.2 for each), while men who were not in a co-residential union had an increased likelihood of reporting each risk behavior (2.2-5.3).

CONCLUSIONS

Men in their 30s, especially those who are not married, engage in risky sexual behaviors. Further studies are needed to assess what contributes to behavioral differences by union status and what types of services might help men in this age-group reduce their risk.