A general measles vaccination campaign in urban Guinea-Bissau: Comparing child mortality among participants and non-participants

BACKGROUND

Measles vaccination campaigns targeting children aged 9-59months are conducted every three years in Guinea-Bissau. Studies have demonstrated beneficial non-specific effects of measles vaccine. We compared mortality one year after the December 2012 measles vaccination campaign in Bissau city for children who received campaign measles vaccine with children who did not receive campaign measles vaccine.

METHODS

Field workers from Bandim Health Project registered all children living in the Bandim Health Project's study area who received measles vaccination at the campaign posts. Children not seen during the campaign were visited at home and campaign participation status was assessed. We compared mortality rates of participants vs. non-participants in Cox regression models.

RESULTS

5633 children aged 9-59months (85%) received campaign measles vaccination and 1006 (15%) did not. During the subsequent year 16 children died. Adjusted for background factors, the hazard ratio (HR) comparing measles vaccinated versus unvaccinated was 0.28 (95% CI: 0.10-0.77). The benefit was larger for girls (HR: 0.17 (0.05-0.59)) and for children who had received routine measles vaccine before the campaign (HR: 0.15 (0.04-0.63)).

CONCLUSIONS

We found indications of strong beneficial non-specific effects of receiving measles vaccine during the 2012 campaign, especially for girls and children with previous routine measles vaccination. Measles vaccination campaigns may be an effective way of improving child survival.

Chemical composition and biological activities of Artemisia judaica essential oil from southern desert of Jordan

ETHNOPHARMACOLOGIC RELEVANCE

Artemisia judaica L. (Arabic name: Beithran), is a medicinal and aromatic plant growing in the valley bottoms of desert areas, particularly in the southern desert of Jordan nearest to the Jordan-Saudi Arabia borders and in Wadi Araba in the Southern Badia. In Jordan, A. judaica is widely used in traditional medicine being recommended by aboriginal Bedouins in the North Badia region of Jordan as calmative. Furthermore, it is used for the treatment of stomach ache, heart diseases, sexual weakness, diabetes, gastro-intestinal disorders and external wounding. Additionally, other folk medicines of the Arabic region commonly use this aromatic plant for the treatment of inflammatory-related diseases, for instance fungal infections, diabetes, atherosclerosis, cancer and arthritis.

AIM OF THE STUDY

Considering the traditional medicinal uses and the lack of scientific studies addressing the cellular and molecular mechanisms behind A. judaica claimed activities, the present study was designed to validate some of the traditional uses ascribed to this species, specifically the antifungal and anti-inflammatory activities of A. judaica essential oil at doses devoid of cytotoxicity to mammalian cells.

MATERIALS AND METHODS

Chemical analysis of A. judaica essential oil isolated by hydrodistillation from aerial parts was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity (minimal inhibitory concentrations and minimal lethal concentrations) was evaluated against yeasts, dermatophyte and Aspergillus strains. In order to deeply explore the mechanisms behind the anti-fungal effect of the essential oil, the germ tube inhibition assay and the biofilms formation assay were evaluated using Candida albicans. The assessment of cell viability was accomplished using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in both hepatocytes and macrophages. Furthermore, the in vitro anti-inflammatory potential of A. judaica oil was evaluated by measuring nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated mouse macrophages.

RESULTS

Oxygen containing monoterpenes are a representative group of constituents (68.7%) with piperitone (30.4%), camphor (16.1%) and ethyl cinnamate (11.0%) as main compounds. The highest antifungal activity of the oil was observed against Cryptococcus neoformans, with a MIC value of 0.16µL/mL. The oil revealed an important inhibitory effect on germ tube formation in C. albicans with 80% inhibition of filamentation at a concentration of 0.16µL/mL. Importantly, the oil also interfered with pre-formed biofilms by reducing the amount of the attached biomass. Furthermore, the essential oil significantly inhibited NO production evoked by LPS on macrophages at concentrations with very low toxicity (0.32µL/mL) or without toxicity (0.16µL/mL) to both macrophages and hepatocytes.

CONCLUSIONS

The present study revealed that A. judaica essential oil from Jordan significantly inhibited germ tube formation and disrupted preformed biofilms of C. albicans, emphasizing the therapeutic potential for the treatment of disseminated candidiasis. Additionally, safe concentrations of this essential oil significantly inhibited NO production elicited by LPS in macrophages, highlighting its potential anti-inflammatory activity. Overall, A. judaica bears promising therapeutic potential for further drug development. Importantly, this work also validates some of the traditional uses of A. judaica.

Community paediatric respiratory infection surveillance study protocol: a feasibility, prospective inception cohort study

INTRODUCTION

Paediatric respiratory tract infections (RTIs) are common reasons for primary care consultations and antibiotic prescribing. Locally relevant syndromic and microbiological surveillance information has the potential to improve the care of children with RTIs by normalising illness (parents) and reducing uncertainty (clinicians). Currently, most RTI studies are conducted at the point of healthcare service consultation, leaving the community burden, microbiology, symptom duration and proportion consulting largely unknown. This study seeks to establish the feasibility of (mainly online) participant recruitment and retention, and the acceptability/comparability of parent versus nurse-collected microbiological sampling, to inform the design of a future surveillance intervention study. Evidence regarding consultation rates and symptom duration is also sought.

METHODS AND ANALYSIS

A community-based, feasibility prospective inception cohort study, recruiting children aged ≥3 months and <16 years and their parents via general practitioner surgery invitation letter, aiming to collect data on 300 incident RTIs by July 2016. Following informed consent, parents provide baseline (demographic) data online, and respond to weekly emails to confirm the absence/presence of new RTI symptoms. Once symptomatic, parents provide daily data online (RTI symptoms, school/day-care attendance, time off work, health service use, medication), and a research nurse visits to collect clinical examination data and microbiological (nasal and saliva) swabs. Parents are invited to provide symptomatic (at nurse visit, but without nurse assistance) and asymptomatic (alone) swabs on recovery. A review of primary care medical notes will gather medical history, health service utilisation, referral and antibiotic prescribing rates. Feasibility will be assessed using recruitment and retention rates, data completeness; and acceptability by quantitative survey and qualitative interviews. Symptomatic parent and nurse swab pairs will be compared for microbe isolation.

Effect of quebracho-chestnut tannin extracts at 2 dietary crude protein levels on performance, rumen fermentation, and nitrogen partitioning in dairy cows

Our objective was to determine the effects of a tannin mixture extract on lactating cow performance, rumen fermentation, and N partitioning, and whether responses were affected by dietary crude protein (CP). The experiment was conducted as a split-plot with 24 Holstein cows (mean ± standard deviation; 669±55kg of body weight; 87±36 d in milk; 8 ruminally cannulated) randomly assigned to a diet of [dry matter (DM) basis] 15.3 or 16.6% CP (whole plot) and 0, 0.45, 0.90, or 1.80% of a tannin mixture in three 4×4 Latin squares within each level of CP (sub-plot). Tannin extract mixture was from quebracho and chestnut trees (2:1 ratio). Dietary CP level did not influence responses to tannin supplementation. A linear decrease in DM intake (25.5 to 23.4kg/d) was found, as well as a linear increase in milk/DM intake (1.62 to 1.75) and a trend for a linear decrease in fat-and-protein-corrected milk (38.4 to 37.1kg/d) with increasing levels of tannin supplementation. In addition, there was a negative linear effect for milk urea N (14.0 to 12.9mg/dL), milk protein yield (1.20 to 1.15kg), and concentration (2.87 to 2.83%). Furthermore, the change in milk protein concentration tended to be quadratic, and predicted maximum was 2.89% for a tannin mixture fed at 0.47% of dietary DM. Tannin supplementation reduced ruminal NH3-N (11.3 to 8.8mg/dL), total branched-chain volatile fatty acid concentration (2.97 to 2.47mol/100mol), DM, organic matter, CP, and neutral detergent fiber digestibility. Dietary tannin had no effect on intake N (587±63g/d), milk N (175±32g/d), or N utilization efficiency (29.7±4.4%). However, feeding tannin extracts linearly increased fecal N excretion (214 to 256g/d), but reduced urinary N (213 to 177g/d) and urinary urea N (141 to 116g/d) excretion. Decreasing dietary CP did not influence milk production, but increased N utilization efficiency (milk N/N intake; 0.27 to 0.33), and decreased milk urea N (15.4 to 11.8mg/dL), ruminal NH3-N (11.0 to 9.3mg/dL), apparent digestibility of DM (66.1 to 62.6%), organic matter (68.2 to 64.3%), and CP (62.9 to 55.9%), as well as urinary N excretion (168 vs. 232g/d). Results of this study indicated beneficial effects of 0.45% tannin extract in the diet on milk protein content. Increasing tannin extract levels in the diet lowered urinary N excretion, but had detrimental effects on DM intake, milk protein content, milk protein yield, and nutrient digestibility.

CONDIÇÃO AMBIENTAL DO MUNICÍPIO DE DIAMANTE DO OESTE – PR

O Indicador de Salubridade Ambiental (ISA) foi criado em 1999 com a finalidade de analisar a eficácia de políticas públicas, a qual busca melhorar a qualidade de vida da população. Ele pode ser aplicado em vários municípios, pois é um instrumento que caracteriza os setores de saneamento básico. O objetivo deste trabalho foi analisar as condições da salubridade ambiental do município de Diamante do Oeste, localizado no estado do Paraná, e avaliar a qualidade dos serviços prestados à cidade. Utilizou-se como base para o estudo dados quantitativos, os mesmos foram inseridos em uma equação pela qual é possível definir a salubridade de uma determinada cidade. Este estudo foi realizado no município de Diamante do Oeste – PR, no qual foi verificado um grau de salubridade de 81,67, que pela metodologia o enquadra como sendo um município salubre, o que pode caracterizar um local com boa qualidade de vida.

Influence of Clinical Communication on Parents' Antibiotic Expectations for Children With Respiratory Tract Infections

PURPOSE

The purpose of this study was to understand clinicians' and parents' perceptions of communication within consultations for respiratory tract infections (RTI) in children and what influence clinician communication had on parents' understanding of antibiotic treatment.

METHODS

We video recorded 60 primary care consultations for children aged 3 months to 12 years who presented with RTI and cough in 6 primary care practices in England. We then used purposive sampling to select 27 parents and 13 clinicians for semistructured video-elicitation interviews. The videos were used as prompts to investigate participants' understanding and views of communication within the consultations. We analyzed the interview data thematically.

RESULTS

While clinicians commonly told parents that antibiotics are not effective against viruses, this did not have much impact on parents' beliefs about the need to consult or on their expectations concerning antibiotics. Parents believed that antibiotics were needed to treat more severe illnesses, a belief that was supported by the way clinicians accompanied viral diagnoses with problem-minimizing language and antibiotic prescriptions with more problem-oriented language. Antibiotic prescriptions tended to confirm parents' beliefs about what indicated illness severity, which often took into account the wider impact on a child's life. While parents understood antimicrobial resistance poorly, most held beliefs that supported reduced antibiotic prescribing. A minority attributed it to resource rationing, however.

CONCLUSIONS

Clinician communication and prescribing behavior confirm parents' beliefs that antibiotics are needed to treat more severe illnesses. Interventions to reduce antibiotic expectations need to address communication within the consultation, prescribing behavior, and lay beliefs.

Unplanned flexible ureteroscopy during percutaneous nephrolithotomy in the prone position

BACKGROUND

Over time, the prone position has been shown to be effective and safe for performing percutaneous nephrolithotomy. One of its disadvantages, however, is the inability to simultaneously perform an ureteroscopy after positioning the patient, which is feasible in the supine position. Our objective is to demonstrate the feasibility of implementing flexible ureteroscopy with the patient in the prone position.

MATERIAL AND METHODS

We present a case of percutaneous nephrolithotomy of partial staghorn calculi in the prone position during which access to the middle calyx was not possible. It was therefore necessary to conduct flexible ureteroscopy. The 64-year-old female patient had consulted for lumbar pain of 6 months of evolution.

RESULTS

We performed percutaneous nephrolithotomy in the prone position. After extracting calculi from the inner calyx and renal pelvis, access to the fragments located in the middle calyx could not be achieved. Rather than performing a new puncture, we decided to enter in a retrograde manner with a flexible ureteroscope, succeeding in extracting the residual calculi, leaving the patient completely free of calculi.

CONCLUSION

In our case, the implementation of retrograde flexible ureteroscopy was feasible without changing the patient's original position.

Artemisia herba-alba essential oil from Buseirah (South Jordan): Chemical characterization and assessment of safe antifungal and anti-inflammatory doses

ETHNOPHARMACOLOGIC RELEVANCE

Artemisia herba-alba Asso ("desert wormwood" in English; "armoise blanche" in French; "shaih" in Arabic), is a medicinal and strongly aromatic plant widely used in traditional medicine by many cultures since ancient times. It is used to treat inflammatory disorders (colds, coughing, bronchitis, diarrhea), infectious diseases (skin diseases, scabies, syphilis) and others (diabetes, neuralgias). In Jordanian traditional medicine, this plant is used as antiseptic and against skin diseases, scabies, syphilis, fever as well as menstrual and nervous disorders.

AIM OF THE STUDY

Considering the traditional medicinal uses and the lack of scientific studies addressing the cellular and molecular players involved in these biological activities, the present study was designed to unveil the antifungal and anti-inflammatory activities of A. herba-alba Asso essential oil at doses devoid of toxicity to mammalian cells.

MATERIALS AND METHODS

Chemical analysis of A. herba-alba essential oil isolated by hydrodistillation from aerial parts was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity (minimal inhibitory concentrations and minimal lethal concentrations) was evaluated against yeasts, dermatophyte and Aspergillus strains. In order to explore the mechanisms behind the anti-fungal effect of the essential oil, the germ tube inhibition assay was evaluated using Candida albicans. The assessment of cell viability was accomplished using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the in vitro anti-inflammatory potential of A. herba-alba oil at the periphery and central nervous system was evaluated by measuring nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated mouse macrophages and microglia, respectively.

RESULTS

Oxygen-containing monoterpenes are the main compounds of the oil, namely 1,8-cineole (20.1%), β-thujone (25.1%), α-thujone (22.9%) and camphor (10.5%). Among the fungal strains tested, the oil demonstrated potential against Trichophyton rubrum and Epidermophyton floccosum, with minimal inhibitory concentration (MIC) and minimal lethal concentration (MCL) values of 0.32 mg/mL and Cryptococcus neoformans with MIC of 0.64 mg/mL. The oil revealed a strong inhibitory effect on germ tube formation in C. albicans with inhibition of filamentation around 90% at a concentration 0.16 mg/mL. Importantly, the essential oil significantly inhibited NO production evoked by LPS without cytotoxicity at concentrations up to 1.25 µL/mL in macrophages and up to 0.32 µL/mL in microglia. Furthermore, evaluation of cell viability in RAW 264.7 macrophages, BW2 microgliacells and HaCaT keratinocytes showed no cytotoxicity at concentrations up to 0.32 μL/mL.

CONCLUSIONS

It was possible to find appropriate doses of A. herba-alba oil with both antifungal and anti-inflammatory activities and without detrimental effects towards several mammalian cell types. These findings add significant information to the pharmacological activity of A. herba-alba essential oil, specifically to its antifungal and anti-inflammatory therapeutic value, thus justifying and reinforcing the use of this plant in traditional medicine.

The CHICO (Children's Cough) Trial protocol: a feasibility randomised controlled trial investigating the clinical and cost-effectiveness of a complex intervention to improve the management of children presenting to primary care with acute respiratory tract infection

INTRODUCTION

While most respiratory tract infections (RTIs) will resolve without treatment, many children will receive antibiotics and some will develop severe symptoms requiring hospitalisation. There have been calls for evidence to reduce uncertainty regarding the identification of children who will and will not benefit from antibiotics. The aim of this feasibility trial is to test recruitment and the acceptance of a complex behavioural intervention designed to reduce antibiotic prescribing, and to inform how best to conduct a larger trial.

METHODS AND ANALYSIS

The CHICO (Children's Cough) trial is a single-centre feasibility cluster randomised controlled trial (RCT) comparing a web-based, within-consultation, behavioural intervention with usual care for children presenting to general practitioner practices with RTI and acute cough. The trial aims to recruit at least 300 children between October 2014 and April 2015, in a single area in South West England. Following informed consent, demographic information will be recorded, and symptoms and signs measured. Parents/carers of recruited children will be followed up on a weekly basis to establish symptom duration, resource use and cost of the illness to the parent until the child's cough has resolved or up to 8 weeks, whichever occurs earlier. A review of medical notes, including clinical history, primary care reconsultations and hospitalisations will be undertaken 2 months after recruitment. The trial feasibility will be assessed by: determining acceptability of the intervention to clinicians and parent/carers; quantifying differential recruitment and follow-up; determining intervention fidelity; the success in gathering the data necessary to conduct a cost-effectiveness analysis; and collecting data about antibiotic prescribing rates to inform the sample size needed for a fully powered RCT.

ETHICS AND DISSEMINATION

The study was approved by the North West-Haydock Research Ethics Committee, UK (reference number: 14/NW/1034). The findings from this feasibility trial will be disseminated through research conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN23547970.

A systematic review of parent and clinician views and perceptions that influence prescribing decisions in relation to acute childhood infections in primary care

OBJECTIVES

To investigate the views of parents, clinicians, and children pertaining to prescribing decisions for acute childhood infection in primary care.

METHODS

A systematic review of qualitative studies. Meta-ethnographic methods were used, with data drawn from the primary studies in an interpretive analysis.

RESULTS

A total of 15 studies met the inclusion criteria. The literature was dominated by concerns about antibiotic over-prescription. Children's views were not reported. Clinicians prescribed antibiotics when they felt pressured by parents or others (e.g. employers) to do so, when they believed there was a clear clinical indication, but also when they felt uncertain of clinical or social outcomes they prescribed "just in case". Parents wanted antibiotics when they felt they would improve the current illness, and when they felt pressure from daycare providers or employers. Clinicians avoided antibiotics when they were concerned about adverse reactions or drug resistance, when certain they were not indicated, and when there was no perceived pressure from parents. Parents also wished to avoid adverse effects of antibiotics, and did not want antibiotics when they would not relieve current symptoms. Some parents preferred to avoid medication altogether. Within paediatric consultations, parents sought a medical evaluation and decision. Primary care clinicians want satisfied parents and short consultations.

CONCLUSIONS

Antibiotic prescriptions for childhood infections in primary care often result from "just in case" prescribing. These findings suggest that interventions which reduce clinician uncertainty regarding social or clinical outcomes and provide strategies to meet parents' needs within a short consultation are most likely to reduce antibiotic prescribing.

"They just say everything's a virus"--parent's judgment of the credibility of clinician communication in primary care consultations for respiratory tract infections in children: a qualitative study

OBJECTIVE

To investigate parents' experiences and views of clinician communication during primary care consultations for respiratory tract infections (RTIs) in children under 12.

METHODS

Semi-structured interviews with 30 parents who had recently consulted for RTI in their child. Purposive sampling was used to interview parents from a range of socio-economic areas.

RESULTS

Parents critically assess the credibility of primary care clinician diagnosis and treatment recommendations based on their perception of the medical evaluation and how well their concerns and expectations have been addressed. A "viral" diagnosis could be perceived as trivializing, particularly when contradicting the parent's perception of severity. Parents expected advice on symptomatic treatment and felt frustrated by 'no treatment' recommendations. Parents commonly reported safety netting advice which was too vague to be useful.

CONCLUSION

Parents' perception of the credibility of the diagnosis and treatment recommendations is influenced both by their expectations and the effectiveness of clinician communication. Opportunities are being missed to inform parents about symptomatic care and when to consult for children with RTIs.

PRACTICE IMPLICATIONS

Clinicians should tailor diagnostic explanations to parental expectations and concerns and address the symptoms of significance to parents. Clinicians should provide advice about symptom relief and more precise safety netting advice.

How communication affects prescription decisions in consultations for acute illness in children: a systematic review and meta-ethnography

Background

Communication within primary care consultations for children with acute illness can be problematic for parents and clinicians, with potential misunderstandings contributing to over–prescription of antibiotics. This review aimed to synthesise the evidence in relation to communication and decision making in consultations for children with common acute illness.

Methods

A systematic search of MEDLINE, EMBASE, CINAHL, PsycINFO, SSCI, SIGLE, Dissertation Express and NHS economic evaluation databases was conducted. Studies of primary care settings in high income countries which made direct observations of consultations and reported qualitative data were included. Included studies were appraised using the process recommended by the Cochrane Qualitative Methods Group. Credibility was assessed as high for most studies but transferability was usually assessed low or unclear. Data were synthesised using a meta–ethnographic approach.

Results

Thirty–five papers and 2 theses reporting on 13 studies were included, 7 of these focussed on children with respiratory tract infections (RTI) and the remaining 6 included children with any presenting illness. Parent communication focussed on their concerns and information needs, whereas clinician communication focussed on diagnosis and treatment decisions. During information exchanges, parents often sought to justify the need for the consultation, while clinicians frequently used problem minimising language, resulting in parents and clinicians sometimes talking at cross–purposes. In the context of RTIs, a range of parent communication behaviours were interpreted by clinicians as indicating an expectation for antibiotics; however, most were ambiguous and could also be interpreted as raising concerns or requests for further information. The perceived expectation for antibiotics often changed clinician decision making into clinician–parent negotiation.

Conclusions

Misunderstandings occurred due to parents and clinicians talking at cross purposes about the ‘seriousness’ of the illness and because parents’ expressions of concern or requests for additional information were sometimes perceived as a challenge to the clinicians’ diagnosis or treatment decision. This modifiable problem may be an important contribution to the unnecessary and unwanted prescribing of antibiotics. Primary care clinicians should be offered training to understand parent communication primarily as expressions of concern or attempts at understanding and always to check rather than infer parental expectations.

Parents' information needs, self-efficacy and influences on consulting for childhood respiratory tract infections: a qualitative study

BACKGROUND

Acute respiratory tract infection (RTI) is the most common reason why parents consult primary care in the UK. Little is known about parents' perceptions of what may help them to make an appropriate decision to consult when their child is ill and how to improve self-care.Using qualitative methods, this study aimed to explore parents' views on support and information needs prior to consulting when children have RTIs with cough, and identify the triggers and barriers to consulting primary care.

METHODS

7 focus groups and 30 semi-structured interviews were held with 60 parents (with children aged 5 months - 17 years) from a range of socio-economic backgrounds. Topics discussed were informed by the Health Belief Model, and explored parents' concerns and beliefs about susceptibility and severity of RTIs, beliefs about the triggers and barriers to consulting, and information and support seeking behaviour undertaken before consulting primary care. Discussions were audio-recorded, transcribed and analysed using thematic methods.

RESULTS

Parents from all socio-economic backgrounds sought information from a wide range of sources about RTIs in children in order to identify which of their child's symptoms should be of concern and trigger a visit to the doctor. The perception of threat to a child of RTI (with cough) was increased with more severe illness and by perceived susceptibility to illness of a particular child; whilst experience with other children increased parental efficacy to cope with childhood cough at home. Psychological models of health behaviour informed the understanding of cultural beliefs and attitudes that underpin health related behaviours.

CONCLUSION

A wide range of perceptions influence the likelihood that parents will seek help from primary care for a child with cough; these perceptions are similar across socio-economic groups. Parents' experience, confidence and efficacy influence the likelihood of consulting primary care for their child's RTI. Parents would value consistent advice from a trusted source that addresses common concerns and supports home care and decision making about help seeking.

Previous transanal full-thickness excision increases the morbidity of radical resection for rectal cancer

AIM

The aim of the study was to determine the impact of primary full-thickness transanal excision (TAE) on the morbidity rate following radical rectal resection for cancer.

METHOD

Fourteen consecutive patients underwent radical resection for lower third rectal cancer following full-thickness TAE without closure of the defect. They were compared with 25 matched patients from a prospective database of 275 rectal resections who had undergone radical resection without previous TAE for lower third rectal cancer (control group). The confounding factors were: age, sex, body mass index (BMI), classification according to the American Society of Anaesthesiologists, administration of neoadjuvant radiotherapy before rectal resection, tumour stage and type of surgical procedure.

RESULTS

There were no deaths. Overall morbidity was 64.3% in the TAE group and 32% in the control group (P = 0.112). Surgical complications were significantly more frequent in the former (57.1%vs 20%; P = 0.048). The frequency of specific surgical site complications, including anastomotic complications and pelvic abscess formation requiring surgical drainage, was significantly higher in the TAE group than in the control group (42.8%vs 8%; P = 0.032). In univariate analysis, the only factors associated with specific surgical site complications were BMI > 27 and TAE before rectal resection.

CONCLUSION

This case-matched study suggests that previous full-thickness TAE increases the risk of surgical complications after radical resection for lower third rectal cancer, including anastomotic dehiscence and pelvic sepsis.

Dissemination of drinking water contamination data to consumers: a systematic review of impact on consumer behaviors

BACKGROUND

Drinking water contaminated by chemicals or pathogens is a major public health threat in the developing world. Responses to this threat often require water consumers (households or communities) to improve their own management or treatment of water. One approach hypothesized to increase such positive behaviors is increasing knowledge of the risks of unsafe water through the dissemination of water contamination data. This paper reviews the evidence for this approach in changing behavior and subsequent health outcomes.

METHODS/PRINCIPAL FINDINGS

A systematic review was conducted for studies where results of tests for contaminants in drinking water were disseminated to populations whose water supply posed a known health risk. Studies of any design were included where data were available from a contemporaneous comparison or control group. Using multiple sources >14,000 documents were located. Six studies met inclusion criteria (four of arsenic contamination and two of microbiological contamination). Meta-analysis was not possible in most cases due to heterogeneity of outcomes and study designs. Outcomes included water quality, change of water source, treatment of water, knowledge of contamination, and urinary arsenic. Source switching was most frequently reported: of 5 reporting studies 4 report significantly higher rates of switching (26-72%) among those who received a positive test result and a pooled risk difference was calculate for 2 studies (RD = 0.43 [CI0.4.0-0.46] 6-12 months post intervention) suggesting 43% more of those with unsafe wells switched source compared to those with safe wells. Strength of evidence is low since the comparison is between non-equivalent groups. Two studies concerning fecal contamination reported non-significant increases in point-of-use water treatment.

CONCLUSION

Despite the publication of some large cohort studies and some encouraging results the evidence base to support dissemination of contamination data to improve water management is currently equivocal. Rigorous studies on this topic are needed, ideally using common outcome measures.

Fabrication and Performance Limits of Sub-0.1 µm Cu Interconnects

As the on-chip interconnect linewidth and film thickness shrink below 0.1 µm, the size effect on Cu resistivity becomes important, and the electrical performance deliverable by such narrow metal lines needs to be assessed critically. From the fabrication viewpoint, it is also crucial to determine how structural parameters affect resistivity in the sub-0.1 µm feature size regime. To evaluate the scaling of resistivity with thickness, we have fabricated a series of Ta/Cu/Ta/SiO2 thin film structures with Cu thickness ranging from 1 µm to 0.02 µm. These test structures revealed a far larger (∼2.3 ×) size effect than that expected from surface scattering. We have also fabricated test structures containing 50-nm-wide Cu lines wrapped in Ta-based liners and embedded in insulating SiO2 using e-beam lithography, high-density plasma etching, ionized PVD Cu deposition, and chemical-mechanical planarization processes. Direct current (16 nA) resistance measurements from these 50-nm-wide Cu lines have also shown a higher- than-expected distribution of resistivity. Cross-sectional TEM and surface AFM observations suggest that the observed extra resistivity increase can be attributed to small grain sizes in ultra- thin Cu films and to Cu/Ta interface roughness. Monte Carlo simulations are used to quantify the extra resistivity resulting from interface roughness.

Effect of Oxygen Exposure and Deposition Environment on Thermal Stability of Ta Barriers To Cu Penetration

The effect of deposition pressure and controlled oxygen dosing on the diffusion barrier performance of thin film Ta to Cu penetration was investigated. In-situ resistivity, Auger compositional profiling, scanning electron microscopy and cross-sectional transmission electron microscopy were used to determine the electrical, chemical and structural changes that occur in Cu/Ta bilayers on Si upon heating. A 20 nm Ta barrier allowed the penetration of Cu at temperatures ranging from 320 to 630°C depending on processing conditions. Barrier failure temperature is dependent upon the deposition pressure and oxygen contamination at the Ta/Cu interface. This indicates the importance of understanding how deposition conditions affect diffusion barrier performance.

Surface Roughening During Titanium Silicide Formation: a Comparison Between Si(100) and Poly-Si Substrates

We demonstrate that the formation of TiSi2 for Ti films deposited on undoped Si(100) substrates leads to rougher surfaces than for Ti films deposited on undoped poly-Si substrates. The successive formations of TiSi2, C49 (high resistivity) and C54 (low resistivity) phases from titanium films deposited on either Si(100) or poly-Si substrates were monitored in situ during rapid thermal annealing using elastic light scattering, x-ray diffraction and resistance measurements. For both types of substrates, the roughening occurs only during the formation of the first TiSi2, phase (C49) by light scattered from lateral length scales of ˜0.5 μm. Atomic force microscopy (AFM) images. quantified using Fourier filtering, are consistent with the light scattering results.

F. Light Scattering Measurement Of Surface Topography During Formation Of Titanium Silicide

The evolution of the surface topography during the phase transformations of titanium silicide has been studied using elastic light scattering at two different collection angles. The light scattering measurements were performed simultaneously with x-ray diffraction and resistance measurements for titanium films deposited on either Si(100) or on poly-silicon substrates. At selected points during annealing, the samples were cooled rapidly to room temperature and analyzed ex situ using Nomarski microscopy. We find that, depending on the detection geometry, the in situ light scattering shows preferentially the formation of the C49 or C54 TiSi2 phase as well as differentiates between inversion and agglomeration on poly-silicon substrates.

Characterization of Plated Cu Thin Film Microstructures

Electroplated Cu was found to have a fine as-plated microstructure, 0.05 ± 0.03 μm, with multiple grains through the film thickness and evidence of twins and dislocations within grains. Over time at room temperature, the grains grew to greater than 1 μm in size. Studied as a function of annealing temperature, the recrystallized grains were shown to be 1.6 ± 1.0 μm in size, columnar and highly twinned. The grain growth was directly related to the time dependent decrease in sheet resistance. The initial grain structure was characterized using scanning transmission electron microscopy (STEM) from a cross-section sample prepared by a novel focused ion beam (FIB) and lift-out technique. The recrystallized grain structures were imaged using FIB secondary electron imaging. From these micrographs, the grain boundary structures were traced, and an image analysis program was used to measure the grain areas. A Gaussian fit of the log-normal distribution of grain areas was used to calculate the mean area and standard deviation. These values were converted to grain size diameters by assuming a circular grain geometry.

Characterization of Plated Cu Thin Film Microstructures

Electroplated Cu was found to have a fine as-plated microstructure, 0.05 ±0.03 μm, with multiple grains through the film thickness and evidence of twins and dislocations within grains. Over time at room temperature, the grains grew to greater than 1 μm in size. Studied as a function of annealing temperature, the recrystallized grains were shown to be 1.6 ± 1.0 μm in size, columnar and highly twinned. The grain growth was directly related to the time dependent decrease in sheet resistance. The initial grain structure was characterized using scanning transmission electron microscopy (STEM) from a cross-section sample prepared by a novel focused ion beam (FIB) and lift-out technique. The recrystallized grain structures were imaged using FIB secondary electron imaging. From these micrographs, the grain boundary structures were traced, and an image analysis program was used to measure the grain areas. A Gaussian fit of the log-normal distribution of grain areas was used to calculate the mean area and standard deviation. These values were converted to grain size diameters by assuming a circular grain geometry.

In-Situ Studies of Silicide Formation in Ti-Ta Bilayer Thin Films on Poly-Si

We have studied the formation of titanium silicides in the presence of an ultra-thin layer of Ta, interposed between Ti and Si. In-situ x-ray diffraction (XRD), resistance measurements and elastic light scattering were used to study the thin film reactions in real time during ramp anneals to 1000°C. On poly-Si substrates the Ta thickness was varied from 0 to 1.5 nm while the Ti thickness was held constant at ∼27 nm. The time-resolved XRD shows that the volume fraction of C40 and metal-rich silicide phases grows with increasing Ta layer thickness. Increased Ta layer thicknesses also delay the growth of the C49 disilicide phase to higher temperatures. Among the Ta thicknesses we examined, 0.3 nm is the most effective in lowering the C49-C54 transformation temperature. Films with Ta layers thicker than 0.5 nm do not completely transform into the C54 phase. The texture of the C54 phase is also sensitive to the Ta thickness. The C54 disilicide film is predominantly (010) textured for the Ti / 0.3 nm Ta sample. The final C54 texture is significantly different for Ta layers thinner or thicker than the optimal 0.3 nm. This suggests that the most effective thickness for lowering the C54 formation temperature is related to the development of a strong (010) texture. The possibility of a template effect by the C40 or metal-rich Ti5Si3 phases is also discussed on the basis of texture considerations.

Composition and anti-fungal activity of the essential oil from Cameroonian Vitex rivularis Gürke

The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts of two populations of Vitex rivularis (subgenus Vitex) collected during the flowering phase of the plants was investigated by gas chromatography and gas chromatography/mass spectroscopy. Sesquiterpene hydrocarbons were the main group in both samples, the main compound being germacrene D. This composition is markedly different from that of the other African species, with the exception of Vitex ferruginea subsp. amboniensis, which belongs to the same subgenus as V. rivularis. Minimal inhibitory concentrations (MIC) and minimal lethal concentrations (MLC) were used to evaluate the anti-fungal activity against yeasts and dermatophyte strains. The oils exhibited significant anti-fungal activity against dermatophyte strains with MIC and MLC values ranging from 0.16 to 0.64 microL mL(-1) and 0.32 to 2.5 microL mL(-1), respectively. For some strains, MIC values were similar to MLC values, indicating the fungicidal activity of the oils. Nevertheless, these oils showed low activity against Candida spp. strains.

Rapid mycobacteria drug susceptibility testing using Gel Microdrop (GMD) Growth Assay and flow cytometry

Control of multi-drug-resistant tuberculosis has been hampered by the lack of simple, rapid and sensitive methods for assessing bacterial growth and antimicrobial susceptibility. Due to the increasing incidence and high frequency of mutations, it is unlikely that culture methods will disappear in the foreseeable future. Therefore, the need to modernize methods for rapid detection of viable clinical isolates, at a minimum as a gold standard, will persist. Previously, we confirmed the feasibility of using the Gel Microdrop (GMD) Growth Assay for identifying sub-populations of resistant Mycobacteria by testing different laboratory strains. Briefly, this assay format relies on encapsulating single bacterium in agarose microspheres and identifying clonogenic growth using flow cytometry and fluorescent staining. In this study, we modified the GMD Growth Assay to make it suitable for clinical applications. We demonstrated the effectiveness and safety of this novel approach for detecting drug susceptibility in clinically relevant laboratory strains as well as clinical isolates of Mycobacterium tuberculosis. Correlation between results using the GMD Growth Assay format and results using two well characterized methods (Broth Microdilution MIC and BACTEC 460TB) was 87.5% and 90%, respectively. However, due to the inherent sensitivity of flow cytometry and the ability to detect small (<1%) sub-populations of resistant mycobacteria, the GMD Growth Assay identified more cases of drug resistance. Using 4 clinically relevant mycobacterial strains, we assessed susceptibility to primary anti-tuberculosis drugs using both the Broth Microdilution MIC method and the GMD Growth Assay. We performed 24 tests on isoniazid-resistant BCG, Mycobacterium tuberculosis H37Ra and Mycobacterium avium strains. The Broth Microdilution MIC method identified 7 cases (29.1%) of resistance to INH and EMB compared to the GMD Growth Assay which identified resistance in 10 cases (41.6%); in 3 cases (12.5%), resistance to INH and EMB was detected only with the GMD Growth Assay. In addition, using 20 Mycobacterium tuberculosis clinical isolates, we compared results using BACTEC 460TB method performed by collaborators and the GMD Growth Assay. Eight of 20 (40%) clinical isolates, which were not identified as drug-resistant using the conventional BACTEC 460TB method, were resistant to 1, 2, or 3 different concentrations of drugs using the GMD Growth Assay (13 cases of 140 experiments). In one case (isolate 1879), resistance to 10.0 microg/ml of STR detected using BACTEC 460TB method was not confirmed by the GMD Growth Assay. Thus, the overall agreement between these methods was 90% (14 discrepant results of 140 experiments). These data demonstrate that the GMD Growth Assay is an accurate and sensitive method for rapid susceptibility testing of Mycobacterium tuberculosis for use in clinical reference laboratory settings.

Differences between the pathogenic processes induced by Steinernema and Heterorhabditis (Nemata: Rhabditida) in Pseudaletia unipuncta (Insecta: Lepidoptera)

Larvae of Pseudaletia unipuncta are moderately susceptible to infections caused by entomopathogenic nematodes, being a desirable host to study pathogenic processes caused by Heterorhabditis bacteriophora, Steinernema carpocapsae, and Steinernema glaseri and their associated bacteria. The ability of the infective stage of these nematodes to invade hosts is quite different. S. carpocapsae invades the highest number of insects and presents the highest penetration rate, followed by H. bacteriophora. Regression analysis between the number of insects parasitized and the number of IJs counted per insect, over time, showed a high correlation for S. carpocapsae whereas for H. bacteriophora it was low. Dose-response was most evident at a concentration below 100 IJs per insect on H. bacteriophora, whereas on S. carpocapsae it was found for doses ranging from 100 to 2,000 IJs. Student's t test analysis of dose-response showed parallel, yet unequal, slopes for both strains of H. bacteriophora, whereas distinct regressions were obtained for S. carpocapsae and S. glaseri, thus, evidencing each species develop a distinct pathogenic process. Insects injected with Photorhabdus luminescens died within 50 h after injection, whereas those treated with X. nematophila died much later. Moreover, the mortality in insects exposed to H. bacteriophora complex and injected with P. luminescens was close, but insects injected with bacteria died faster. Insect mortality in treatments with complexes S. carpocapsae and S. glaseri was significantly higher than that which was observed in insects injected with symbiotic bacteria.

[Medullary carcinoma of the stomach]

The aim of this work is to show the important histiocytic oblation present in a case of stomach medullary carcinoma, marked with silver technique of Del Río Hortega. This carcinoma is poor differentiated with a predominant lymphoid infiltrate, of better prognosis, that shares many characteristic with medullary carcinoma of breast, lung, nasopharynx, thymus and salivary gland. Histologic techniques: Hematoxilin & Eosin, PAS, PAS-Alcian blue, Alcian blue, Masson's trichrome, macrophagues Del Río Hortega-Polak, and reticulin Del Rio Hortega silver impregnations techniques. Gastric medullary carcinoma shows an important lymphoid infiltration T and B, and dendritic, plasmodials and giant multinucleated macrophagues in close relations with neoplasic cells. The results suggest that Epstein-Barr virus (EBV) becomes associated with gastric medullary carcinoma.

Mechanisms for Enhanced Formation of the C54 Phase of Titanium Silicide Ultra-Large-Scale Integration Contacts

▪ Abstract  Three methods have recently been developed to enhance the formation of the low-resistivity C54 phase of TiSi2, the most widely used silicide contact in ultra-large-scale integration devices. These methods are (a) ion implantation of a transition metal into the Si before Ti deposition; (b) deposition of a thin transition metal interlayer between the Si and Ti; and (c) codeposition of Ti alloyed with a transition metal. Each of these methods decreases the C49-to-C54 transformation temperature by >100°C and improves the probability of phase formation in narrow lines by increasing the nucleation site density. In this paper, we identify the aspects of phase formation that are shared by these three methods, review the methodology by which they were developed, and summarize the applications to silicon devices. Mechanisms that are responsible for the enhanced formation of C54 TiSi2 are reviewed, based on a combination of temperature-controlled in situ measurements of resistance, X-ray diffraction, and optical scattering, coupled with ex situ studies of phase formation and morphology. The main mechanisms are identified as enhanced nucleation of the C54 phase by a reduction of grain size in the C49 phase and the creation of crystallographic templates of the C40 disilicide phase and the metal-rich Ti5Si3 phase.

[Prevalence of several cardiovascular risk factors in a population in the municipality of Viseu]

STUDY OBJECTIVE

To assess the prevalence of the main changeable cardiovascular risk factors (hypertension, hypercholesterolemia and smoking) in the population of the Viseu municipality.

MATERIAL AND METHODS

The population was obtained through a publicity campaign in local radios and on lighted placards in the town of Viseu. We chose a set of volunteers above 20 years of age, who answered a questionnaire about smoking habits, academic qualifications, profession and residence. After the inquiry, the total cholesterol and blood pressure were determined. We considered hypertension (HBP) values > or = 140/90 mmHg and hypercholesterolemia > 200 mg/dl.

RESULTS

1852 persons were inquired (3.2% of the population of the Viseu municipality) 1173 of which were females. According to the age groups, we verified that the ages between 50 and 69 years represented 47.9% of the total amount of volunteers. In what concerns smoking habits, we found a prevalence of 9.1% (15.9% in males and 5.2% in females). In the study of the prevalence of HBP we found a value of 38.5%, higher in males (42.8%) than in females (35.9%). The prevalence of hypercholesterolemia found was 34.9% (no significant differences between the sexes).

CONCLUSION

In comparison with other studies carried out in the Portuguese population, a low prevalence of smoking habits, high hypertension and similar hypercholesterolemia were found.

[Living conditions of prostitutes: consequences for the prevention of HIV infection]

Since 1990, several community-based interventions have been set up for populations of prostitutes in France with the principal objective of preventing HIV infection in prostitutes and their sexual partners. Field workers have suggested that extremely precarious living conditions are a major obstacle for the diffusion of prevention messages. A multidisciplinary working group thus set up a study in order to determine which living conditions could affect the adoption of behaviour at low risk for HIV infection. In May 1995, six of the seven teams conducting prevention actions among prostitutes in France used a short standardised questionnaire to collect information including type of housing, health insurance cover, physical aggressions, drug use. It was planned to collect data from all persons attending the drop-in centres. A total of 355 questionnaires were completed (sampling was exhaustive for 3 of the 6 teams). The population comprised women, men and transvestites. The median age was 28 years. Only 39% (135/348) of the subjects had access to health insurance. Approximately 50% (160/324) of the persons lived in precarious accommodation (hotel or no fixed address) and 33% (119/355) had been victims of physical aggressions during the 5 months preceding the study. Transvestites and young people had the most precarious living conditions. Despite the limits of this study due to the difficulty in carrying out a survey in this very marginalised population, the unique information collected may enable community health action strategies to be suitably adapted. In particular, it is important to improve partnership between field workers and existing social and health services, to improve access to better accommodation, health care and physical security while disseminating prevention messages and distributing condoms.

[A left intraventricular thrombus in an adolescent. Its relationship to the anticardiolipin antibody syndrome]

The authors are going to present the clinical case of a 14-years-old female patient who has got an anticardiolipin antibodies syndrome, a theme to which they add some ideas concerning physiopathology and diagnosis criteria. They'd like to emphasise the echocardiographic observation, which allowed them to find out and follow the evolution of a left sided intraventricular thrombus, the real cause for the systemic thrombosis.

[The Ellis-Van Creveld syndrome. Apropos 2 clinical cases]

The chondroectodermal dysplasia--Ellis-Van Creveld Syndrome--is an unusual form of congenital disease, genetically transmitted with a recessive autosomal pattern, which involves the skeletal system, nails and teeth. In about 50 to 60 percent of cases, the affected individuals show cardiac abnormalities, and the most common are single atrium, large atrial septal defect, ostium primum type. Other abnormalities may accompany these lesions, such as aortic atresia, hypoplasia of the ascending aorta or of the left ventricle. About half of the patients die in the childhood due to cardiorespiratory complications. Two cases are described with this syndrome, a male and a female, with 54 and 45 years old respectively; they were followed in our Departments and showed congestive heart failure and single atrium. These cases led us to review the subject; we believe that the unusual longevity of these patients can be related to their relatively benign cardiac disease.

Activation of human platelets by cocaine

BACKGROUND

Cocaine ingestion has been associated with thrombosis of coronary as well as peripheral arteries, but the mechanism by which cocaine promotes thrombus formation is unknown. Accordingly, we determined whether cocaine activates human platelets by flow cytometric analysis of whole blood to which cocaine was added.

METHODS AND RESULTS

Activated platelets were detected by "two-color" flow cytometric analysis of the binding of fluorescently labeled antibodies directed against either platelet-associated fibrinogen or P-selectin, which are found on the surface of platelets only after stimulation. Platelets were distinguished from other constituents of whole blood by their ability to bind an anti-glycoprotein Ib antibody bound to both activated and resting platelets. Incubation of whole blood with cocaine, in concentrations of 10 microM to 13 mM, induced significant increases in both platelet-associated fibrinogen (range of increase, 45 +/- 12% to 125 +/- 40%) and P-selectin expression (36 +/- 15% to 112 +/- 24%). In platelets suspended in either buffer or plasma, however, P-selectin expression was detected only at the highest cocaine concentration (85 +/- 13% increase in plasma and 59 +/- 7% in buffer). Neither aspirin nor the ADP scavenger apyrase inhibited cocaine-induced P-selectin expression. Cocaine inhibited the uptake of 14C-radiolabeled serotonin by platelets (IC50, 8.7 microM). P-selectin expression and fibrinogen binding were found after the addition of cocaine alone to blood taken from some but not all donors; however, platelet activation in response to submaximal concentrations of the agonists ADP or epinephrine was enhanced by a low concentration of cocaine added to blood from every donor.

CONCLUSIONS

Cocaine, in concentrations similar to those found clinically, induces activation of individual platelets studied in whole blood from some but not all donors, and platelet response to physiological agonists is enhanced by cocaine. Thus, cocaine-induced platelet activation may contribute to thrombosis following cocaine ingestion.

Membrane glycoproteins and platelet cytoskeleton in immune complex-induced platelet activation

To clarify the mechanism of platelet activation by immune complexes and the possible involvement of surface glycoproteins (GPs), we studied platelet activation induced by heat-aggregated IgG (HAG). We examined the effects of monoclonal antibodies (MoAbs) against GPIb, GPIIb/IIIa, and the Fc receptor on resting platelets and on platelets stimulated by HAG. HAG increased the cytosolic ionized calcium concentration ([Ca2+]i) and stimulated protein (P47 and P20) phosphorylation, phosphatidic acid (PA) synthesis, serotonin secretion, and platelet aggregation. IV.3, an anti-Fc gamma RII receptor MoAb, inhibited HAG binding to platelets and all subsequent platelet responses. Like IV.3, MoAbs against GPIIb/IIIa (Tab, 10E5, AP-3) or GPIb (AP-1, 6D1) strongly inhibited platelet activation by HAG. However, while anti-GPIIb/IIIa MoAbs inhibited binding of IV.3 and HAG to platelets, anti-GPIb MoAbs had little effect on platelet binding of IV.3 or HAG. These observations suggest a close topographical and functional association of GPIIb/IIIa with Fc gamma RII in the platelet response to HAG. Cytochalasin B, an inhibitor of actin polymerization, also inhibited platelet activation but not HAG or IV.3 binding. Measurement of the fluorescence of 7-nitrobenz-2-oxa-1,3-(NBD)-phallacidin, a specific marker for filamentous actin (F-actin), showed that both cytochalasin B and AP-1 blocked the increase of F-actin induced by HAG. The common effects of anti-GPIb MoAbs and of cytochalasin B suggest that unlike the activity of GPIIb/IIIa, the ability of anti-GPIb to inhibit the activation of platelets by immune complexes is associated with perturbation of the cytoskeleton.

Heterogeneity in filamentous actin content among individual human blood platelets

The content of filamentous actin in individual platelets was measured by flow cytometry, using a fluorescent probe specific for filamentous actin (F-actin), 7-nitrobenz-2-oxa-1,3-phallacidin (NBD-phallacidin). NBD-phallacidin binding to fixed platelets was specific in that either pretreatment of platelets with unlabeled phallacidin or absorption of NBD-phallacidin by rabbit skeletal F-actin, but not globular actin (G-actin), resulted in a significant loss in the bound fluorescent probe. Mean NBD-phallacidin binding to fixed platelets varied with the agonist and paralleled the changes in F-actin reported with the DNAse I inhibition assay. (1) NBD-phallacidin binding increased with stimulation by ADP, U46619 (a prostaglandin H2 analogue), or collagen and paralleled shape change. (2) Epinephrine did not increase NBD-phallacidin binding. (3) Platelets treated at 4 degrees C contained more F-actin than did platelets kept at 37 degrees C. (4) Cytochalasin D (10 mumol/L) inhibited the increase of phallacidin binding to individual platelets stimulated by either ADP or U46619. In measurements of cytosolic free calcium concentration ([Ca2+]i) by flow cytometry in Indo-1-loaded platelets, ADP's dose-response for actin polymerization was similar to that for calcium mobilization. As shown by flow cytometry, a tail population that had a minimal increase in F-actin upon stimulation with ADP or U46619 also contained the platelets with the least forward and right angle light scattering, which are functions of platelet size and shape. When platelets treated with NBD-phallacidin were incubated with S12-murine monoclonal antibody (a marker of alpha-granule secretion detected by phycoerythrin-conjugated antimouse IgG second antibody), phallacidin fluorescence paralleled S12 binding. Thus, human blood platelets are heterogeneous in regard to actin polymerization at rest and in association with platelet activation; different degrees of phallacidin binding may identify functionally different platelet populations.