Disrupting the wall accumulation of human sperm cells by artificial corrugation

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells ∼60 μm long, strongly confined to ∼25 μm shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.

Susceptibility status of Aedes aegypti (L.) (Diptera: Culicidae) to temephos in Venezuela

BACKGROUND

Temephos is an insecticide widely used in Venezuela to control the proliferation of the larvae of Aedes aegypti (L.), the principal vector of dengue virus. The aim of this study was to identify the susceptibility to temephos of Ae. aegypti in four locations in western Venezuela: Lara, Tres Esquinas, Ureña and Pampanito. Larval bioassays were conducted on samples collected in 2008 and 2010, and the levels of α- and β-esterases, mixed-function oxidases, glutathione-S-transferase and insensitive acethyl cholinesterase were determined.

RESULTS

Larval populations from western Venezuela obtained during 2008 and 2010 were found to be susceptible to temephos, with low resistance ratios and without overexpression of enzymes.

CONCLUSIONS

The low RR values reveal the effectiveness of temephos in controlling the larval populations of Ae. aegypti. Control strategies must be vigorously monitored to maintain the susceptibility to temephos of these populations of Ae. aegypti.

Resistance to malathion and deltamethrin in Aedes aegypti (Diptera: Culicidae) from western Venezuela

Resistance to the insecticides deltamethrin and malathion and the enzymes associated with metabolic resistance mechanisms were determined in four field populations of Aedes aegypti (L.) from western Venezuela during 2008 and 2010 using the bottle assay and the microplate biochemical techniques. For deltamethrin, mortality rates after 1 h exposure and after a 24-h recovery period were determined to calculate the 50% knock-downconcentration (KC50) and the lethal concentration (LC50), respectively. For malathion, mortality was recorded at 24 h to determine the LC50. For deltamethrin, resistance ratios of knock-down resistance and postrecovery were determined by calculating the RRKC50 and RRLC50, comparing the KC50 and LC50 values of the field populations and those of the susceptible New Orleans strain. Knock-down resistance to deltamethrin was moderate in the majority of the populations in 2008 (RRKC50 values were between 5- and 10-fold), and only one population showed high resistance in 2010 (RRKC50 > 10-fold). Moderate and high postrecovery resistance to deltamethrin was observed in the majority of the populations for 2008 and 2010, respectively. There was significantly increased expression of glutathione-S-tranferases and mixed-function oxidases. All populations showed low resistance to malathion in 2008 and 2010 with significantly higher levels of alpha-esterases for 2008 and 2010 and beta-esterases for 2008.

Evaluation of the effectiveness of insecticide treated materials for household level dengue vector control

Objective

To assess the operational effectiveness of long-lasting insecticide treated materials (ITMs), when used at household level, for the control of Aedes aegypti in moderately infested urban and suburban areas.

Methods

In an intervention study, ITMs consisting of curtains and water jar-covers (made from PermaNet) were distributed under routine field conditions in 10 clusters (5 urban and 5 suburban), with over 4000 houses, in Trujillo, Venezuela. Impact of the interventions were determined by comparing pre-and post-intervention measures of the Breteau index (BI, number of positive containers/100 houses) and pupae per person index (PPI), and by comparison with indices from untreated areas of the same municipalities. The effect of ITM coverage was modeled.

Results

At distribution, the proportion of households with ≥1 ITM curtain was 79.7% in urban and 75.2% in suburban clusters, but decreased to 32.3% and 39.0%, respectively, after 18 months. The corresponding figures for the proportion of jars using ITM covers were 34.0% and 50.8% at distribution and 17.0% and 21.0% after 18 months, respectively. Prior to intervention, the BI was 8.5 in urban clusters and 42.4 in suburban clusters, and the PPI was 0.2 and 0.9, respectively. In both urban and suburban clusters, the BI showed a sustained 55% decrease, while no discernable pattern was observed at the municipal level. After controlling for confounding factors, the percentage ITM curtain coverage, but not ITM jar-cover coverage, was significantly associated with both entomological indices (Incidence Rate Ratio = 0.98; 95%CI 0.97–0.99). The IRR implied that ITM curtain coverage of at least 50% was necessary to reduce A. aegypti infestation levels by 50%.

Conclusion

Deployment of insecticide treated window curtains in households can result in significant reductions in A. aegypti levels when dengue vector infestations are moderate, but the magnitude of the effect depends on the coverage attained, which itself can decline rapidly over time.

An estimated 40% of the world's population lives at risk of contracting dengue, and it inflicts a significant health, economic and social burden on the populations of endemic areas. In the absence of a vaccine, vector control is the only available strategy to prevent transmission. Some control methods against Aedes aegypti (the main dengue vector) have been successful in reducing vector infestation levels, but rarely sustained the reductions for a prolonged period. We report here on the first effectiveness trial of insecticide treated curtains and jar covers against A. aegypti implemented under ‘real-life’ conditions. The coverage of tools was high at distribution, but declined quickly over the 18 months of follow up. The vector infestation levels showed a sustained 55% decrease in the intervention clusters, while no discernable pattern was observed at the municipal level. At least 50% curtain coverage was needed to reduce A. aegypti infestation levels by 50%. We concluded that deployment of insecticide treated window curtains in households can result in significant reductions in dengue vector levels, which are related to dengue transmission risk. The magnitude of the effect depends on the curtain coverage attained, which itself can decline rapidly over time.

Survey of T-2 and HT-2 toxins in soybean and soy meal from Argentina using immunoaffinity clean-up and high performance liquid chromatography

Soybean and soy meal samples collected during the harvest season 2008-2009 in the soybean-growing area of Córdoba Province in Argentina were analysed for T-2 and HT-2 toxins occurrence. These mycotoxins were detected using HPLC analysis with fluorescence detection after derivatisation with 1-anthronylnitrile and immunoaffinity column clean-up. Characteristics of in-house validated method such as accuracy, precision, detection and quantification limits were defined by means of recovery test with spiked soybean and soy meal samples. Mean recoveries for T-2 within the spiking range 125-500 µg/kg, were 90.9 and 81.3% for soybean and soy meal, respectively with a withinlaboratory relative standard deviation <10%. Analysis of samples spiked with HT-2 in the same range gave a mean recovery of 70.2 and 77.5% for soybean and soy meal, respectively, with relative standard deviations <12%. The limit of detection for the method was 25 µg/kg for T-2 and HT-2, based on a signal-to-noise ratio 3:1 and the limit of quantification was established as three times the detection limit. Out of 64 samples, only two soybean samples showed contamination with A-type trichothecenes evaluated. Confirmatory analyses of the contaminated samples were performed by LC-MS/MS. This study demonstrated low incidences and levels of T-2 and HT-2 in soybean harvested among the areas in the Cordoba Province.

The correlation between tumour regression grade and lymph node status after chemoradiation in rectal cancer

OBJECTIVE

To determine the correlation between tumour response to preoperative RCTX and lymph node status, an established parameter of clinical outcome.

METHOD

After IRB approval, 86 consecutive rectal cancer patients who received preoperative RCTX were identified. Fifty seven were males. Mean age 62 years. Preoperative staging by ultrasound was available in 60 patients. Radiotherapy consisted of (40-60 g) and chemotherapy of 5-FU infusion (1500 mg/m(2) week), assessed using Dworak's system.

RESULTS

Tumour response according to Tumor regression grade (TRG) were: TRG 0: 8 (9.3%); TRG 1: 15 (17.4%); TRG 2: 14 (16.2%); TRG 3: 31 (36%); TRG 4: 18 (20%). Eighteen patients had tumour stage 0 (20.9%); while 8 (9.2%), 28 (32.1%), 30 (34.5%) and three had tumours stages 1, 2, 3 and 4 respectively. Evaluation of nodal status revealed no involvement in 65 patients (N0), and positive nodes in 21 (14 N1, 7 N2). Response to RCTX was significantly associated with node stage, hence individuals without node involvement (N0) had 66% of positive tumour response (TRG 4), while individuals with node metastasis had less response to RCTX (TRG 0, 1 and 2) 35% N1 and 14% for N2 (P = 0.007). Node status was independently associated to poor response to preoperative RCTX, even after adjusting for tumour stage, age and gender (OR 0.02, 95% CI 0.0009-0.67).

CONCLUSION

Tumour shrinkage by preoperative RCTX appears to correlate with lymph node metastasis suggesting that neoadjuvant RCTX may have a positive impact in overall patient survival.

Factors influencing the case-fatality rate of Legionnaires' disease

SETTING

The extent of the public health problem posed by Legionnaires' disease (LD) is not always well- appreciated.

OBJECTIVE

To determine the characteristics and factors associated with the case fatality rate (CFR) of LD in Catalonia, Spain.

DESIGN

Confirmed cases of LD reported during 1993-2004 were studied. Age, sex, hospitalisation, the type of diagnostic confirmation test and the personal risk factors for LD of cases were collected. Comparative bivariate and multivariate analyses according to origin (community-acquired or nosocomial) and nature (sporadic or outbreaks) were performed.

RESULTS

Of 1938 cases reported, 164 died (case-fatality rate [CFR] 8.5%). The CFR fell from 35% in 1993 to 5.6% in 2004, and was higher in sporadic than in outbreak-associated cases (10% vs. 4.7%) and in nosocomial than community-acquired cases (31.7% vs. 6.8%). In community-acquired cases, the CFR was associated with age >70 years (OR 3.42, 95%CI 2.02-5.79), cancer (OR 4.58, 95%CI 2.36-8.90) and diagnostic confirmation methods other than Legionella urinary antigen test. The CFR of nosocomial cases was not associated with any of these factors.

CONCLUSIONS

The CFR of LD fell during the study period due to the incorporation of new diagnostic techniques and improved detection of outbreaks.

The influence of public or private paediatric health care on vaccination coverages in children in Catalonia (Spain)

BACKGROUND

Maintaining high vaccination coverages is necessary in order to control vaccine-preventable diseases. We studied vaccination coverages in a representative sample of 630 children aged <3 years in Catalonia in order to determine the relationship between vaccination coverages and socioeconomic factors.

METHODS

Sampling was carried out in a representative sample of the health regions in Catalonia stratified according to habitat. A sample of 630 parents of children aged <3 years born in October 2001 were interviewed by telephone. Information collected included sociodemographic data, type of health care provider (public or private) and information on vaccination coverage for the basic plus booster immunization series (BBI) which consisted of: four DTP, four OPV, one MMR and the doses of Hib and MenC necessary according to age of administration of the first dose.

RESULTS

A total of 87.62% of the children were vaccinated with the BBI series, and no statistically significant differences in coverage between public (87.93%) and private (88.30%) paediatric providers, or between social classes (high: 87.58%, low: 88.81%) were found. Vaccination coverage was associated with attending a day-care centre (OR: 1.89; 95% CI: 1.12-3.21) and maternal university education (OR: 1.84; 95% CI: 1.01-3.33).

CONCLUSION

Vaccination coverages are high and are similar between types of provider, probably due to preventive policies which have made a concerted effort to ensure universal vaccination.

Epidemiology of hepatitis A before and after the introduction of a universal vaccination programme in Catalonia, Spain

A universal vaccination program for preadolescents, aged 12 years, with the hepatitis A + B vaccine was introduced in 1998 in Catalonia (Spain) with the aim of protecting the whole population against hepatitis A. The hepatitis A + B vaccine program replaced the hepatitis B vaccination program for preadolescent started in 1991. The impact of the hepatitis A + B vaccination program was studied by assessment of the trend of reported cases of hepatitis A. All cases of viral hepatitis reported from 1992 to 2006 were included in the study. To evaluate changes in the epidemiology of hepatitis A, two periods were considered: a prevaccination period (1992-1998) and a post-vaccination period (2001-2006). The ratios of the rates were calculated according to age and sex. The comparison of rates and proportions was made by calculation of the normal z statistic. A total of 7536 cases of viral hepatitis were reported, of which 4109 (54.52%) were hepatitis A. The incidence rate of hepatitis A fell from 5.44 per 100 000 person-years in the prevaccination period to 3.02 in the post-vaccination period. In males, the rate fell from 6.85 to 3.89 and in females from 4.10 to 2.18. The male-female ratio of incidence rates was lower in the post-vaccination period. In males the global decline of incidence rate was 43.26% and in females 46.96%. The greatest decline occurred in the 15 to 19 years age group in both sexes (79.1% in men and 78.34% in women) but declines in the 10-14 years age group were also very important (69.21% and 67.88%, respectively). In conclusion, hepatitis A incidence fell in Catalonia in the post-vaccination period in vaccinated adolescents and also in other unvaccinated groups who have benefited from the indirect effects of the vaccination program.

[Preliminary evaluation of maggot (Diptera: Calliphoridae) therapy as a potential treatment for leishmaniasis ulcers]

INTRODUCTION

Maggot debridement therapy has been widely used for treating a variety of scarred-over soft-tissue wounds. Published accounts record several illnesses in which treatment with larval therapy has promoted injury healing in conjunction with infection by bacterial pathogens resistant to conventional antibiotics.

OBJECTIVE

An initial test of the maggot therapy was developed for cutaneous injuries produced by Leishmania amazonensis.

MATERIALS AND METHODS

An experimental design based on an animal model with three replicates in Mesocricetus aureatus (Rodentia: Muridae) was used to evaluate size variation lesion before and after after larval therapy with Lucilia sericata maggots . The criteria used for therapy evaluation were lesion size, maggot application time, and presence or absence of edema and secretions.

RESULTS

Effective scarring and wound healing was observed after therapy with L. sericata larvae, i.e. 80% to 100% lesion area reduction after 12 hours.

CONCLUSION

The preliminary results suggest that fly maggots of L. sericata have a potential use as natural medical and veterinary alternative therapy for the cutaneous leishmaniasis.

Use of the pupal/demographic-survey technique to identify the epidemiologically important types of containers producing Aedes aegypti (L.) in a dengue-endemic area of Venezuela

As dengue continues to emerge as a major public-health problem world-wide, efforts to control the dengue vector Aedes aegypti must become more effective and efficient. Results from larval and pupal surveys applied in Venezuela illustrate the uniqueness of the information gained from pupal surveys; information that is lost when traditional Stegomyia indices are calculated. As most Ae. aegypti pupae will emerge to become adults, controlling the containers that produce the most pupae could have the greatest impact on the adult population. Pupal-survey results in Venezuela showed that large (150- to 200-litre) water drums produce the greatest number of pupae throughout the year. In the rainy season, approximately 70% of all pupae are found in these drums or in tyres, buckets and tanks. Over 80% of pupae in the dry season are found in drums and tanks alone. By targeting only those domestic breeding containers that produce the greatest number of pupae, control efforts may be streamlined to have the greatest impact on reducing the local adult Ae. aegypti population.

Multiplex-PCR for detection of natural Leishmania infection in Lutzomyia spp. captured in an endemic region for cutaneous leishmaniasis in state of Sucre, Venezuela

We studied the natural infection of Lutzomyia (Lutzomyia) sp. with Leishmania in endemic foci of cutaneous leishmaniasis in the Paria peninsula, state of Sucre, Venezuela. Sand flies were collected between March 2001 and June 2003, using Shannon light-traps and human bait. Of the 1291 insects captured, only two species of phlebotomines were identified: L. ovallesi (82.75%) and L. gomezi (17.42%). A sample of the collected sand flies (51 pools of 2-12 individuals) were analyzed by using a multiplex-PCR assay for simultaneous detection of New Word Leishmaniaand Viannia subgenera. The results showed a total of 8 pools (15.68%) infected; of these, 7 were L. ovallesi naturally infected with L. braziliensis (2 pools) and L. mexicana (5 pools) and 1 pool of L. gomezi infected by L. braziliensis.

Pancreatic function after severe acute biliary pancreatitis: the role of necrosectomy

OBJECTIVES

To investigate the recovery of pancreatic function after severe acute biliary pancreatitis (ABP), especially the influence of necrosectomy on endocrine and exocrine functions.

METHODS

Prospective cohort study including 39 patients with severe ABP. According to need or no need for surgical necrosectomy, patients were further subdivided into 2 groups. Functional pancreatic evaluation was carried out 12 months after the ABP episode. Endocrine function was evaluated by an oral glucose tolerance test and exocrine function by fecal fat excretion, fecal chymotrypsin (FQ), and secretin-cerulein tests (SCT).

RESULTS

Most of the patients with necrosectomy had an abnormal exocrine pancreatic function, with steatorrhea in 25%. In the group without surgery, exocrine function was pathologic in only 13.3% and there were no cases of steatorrhea. Endocrine function was pathologic in 75% of patients undergoing necrosectomy versus 26.7% in the nonoperated group. In this latter group, the patients with abnormal endocrine function did not require insulin therapy, while in 33.3% of patient in the necrosectomy group insulin was necessary.

CONCLUSIONS

In our homogeneous series of severe ABP, necrosectomy impaired significantly pancreatic endocrine and exocrine function. On the other hand, most patients with the same origin and severity index, but without surgical debridement, maintained normal pancreatic function.

Rotavirus y adenovirus 40–41 como causantes de gastroenteritis infantil

Introducción

El rotavirus es la principal causa de diarrea grave en niños menores de 5 años, y ocasiona una elevada morbilidad y mortalidad a escala mundial. El objetivo de este trabajo ha sido conocer la epidemiología de los virus entéricos que se declaran en el Sistema de Notificación Microbiológica de Cataluña (SNMC), rotavirus y adenovirus 40-41, y valorar la importancia que tienen en el contexto de la enfermedad entérica.

Material y métodos

Se han revisado retrospectivamente las declaraciones que realizan los laboratorios de los hospitales que participan en el SNMC durante los años 1995-2002. Los casos de gastroenteritis aguda se han diagnosticado por detección de antígeno en heces. Las variables analizadas han sido: edad, sexo, mes y año de aislamiento. Como métodos estadísticos se han utilizado el test de la ?2 y test de Fisher; las proporciones se han comparado utilizando la prueba binomial y el nivel de significación estadística se ha establecido en 0,05.

Resultados

Se han detectado 6.708 (94,3%) rotavirus y 409 (5,7%) adenovirus 40-41. Las gastroenteritis agudas virales han presentado mayor morbilidad en niños pequeños menores de 2 años: el 76 y el 68% de rotavirus y adenovirus, respectivamente, se han concentrado en este grupo de edad. El rotavirus se ha aislado principalmente en invierno (68%), mientras que el adenovirus, aunque se ha presentado estable en todas las estaciones, ha sido más frecuente en otoño (35,2%). Respecto a las enteritis, bacterianas y virales, vigiladas en el SNMC, el rotavirus y el adenovirus han supuesto la segunda y la cuarta causa etiológica, respectivamente, en los niños menores de 5 años, después de Campylobacter y Salmonella.

Conclusiones

De los diferentes virus que pueden causar gastroenteritis aguda, hay otros virus con frecuencias elevadas, como calici-virus y astrovirus, que no se buscan sistemáticamente, por lo que hay que valorar las frecuencias con prudencia. A pesar de esto, el rotavirus es la principal causa de la gastroenteritis viral, y afecta principalmente a edades tempranas de la vida, sobre todo a niños de 1 a 11 meses, con un claro predominio en invierno. Respecto al adenovirus 40-41, se ha presentado preferentemente en niños menores de 2 años y con mayor frecuencia en otoño. La vacunación contra el rotavirus es prioritaria para poder disminuir el alto índice de morbilidad y mortalidad que ocasiona esta enfermedad.

Comparative vectorial efficiency of Lutzomyia evansi and Lu. longipalpis for transmitting Leishmania chagasi

The infection rates and development of Leishmania chagasi in two sandfly species, Lutzomyia evansi and Lutzomyia longipalpis, were evaluated under natural and experimental conditions. Natural infection rates of Lu. evansi in San Andrés de Sotavento (Colombia) and Montañas de Peraza (Venezuela) (0.05 and 0.2%, respectively) were similar to those previously recorded for this species in Colombia and Venezuela and for Lu. longipalpis in many foci of American Visceral Leishmaniasis (AVL). Both sand fly species were able to support the development of two Colombian strains of L. chagasi experimentally acquired from dogs, hamsters or membrane feeders. However, the experimental infection rates and the sequence of parasite development in the guts of these sand flies revealed that parasite colonisation, differentiation, migration and attachment were more frequent and uniform in Lu. longipalpis than in Lu. evansi. This is consistent with a more recent association between L. chagasi and Lu. evansi, and these results might help to explain the irregularity of AVL outbreaks in foci where Lu. evansi has been reported as the sole vector.

Molecular identification of vectors of Leishmania in Colombia: mitochondrial introgression in the Lutzomyia townsendi series

The identity of the sandfly vectors of Leishmania braziliensis in Valle del Cauca Department, Colombia, was originally given as Lutzomyia townsendi, but then changed to L. youngi, another member of the L. townsendi series (Verrucarum group) with isomorphic females. To identify members of this series in Valle del Cauca, we analyzed the nuclear gene elongation factor-alpha (EF-alpha) and the mitochondrial gene cytochrome b (Cyt b). DNA sequences from the L. verrucarum series (L. columbiana, L. evansi and L. ovallesi) were used as outgroups. Flies from two locations on the western cordillera of the Andes were identified as L. townsendi s.s., according to male morphology and distinctive gene lineages. In the third location, on the central cordillera of the Andes, most specimens were identified as belonging to a geographical population of L. youngi, according to male morphology, an EF-alpha lineage shared with L. youngi from the Venezuelan-type locality, and a distinctive Cyt b sub-lineage. All other specimens were identified as L. youngi with the introgressed Cyt b sequences of L. townsendi. Such interspecific introgression implies that vectorial traits and ecological associations may no longer be viewed as fixed properties of different morphospecies.

Effect of a second bloodmeal on the oesophagus colonization by Leishmania mexicana complex in Lutzomyia evansi (Diptera: Psychodidae)

Migration and colonization of the oesophagus by Leishmania mexicana parasites were enhanced after digestion of a second bloodmeal intake in Lutzomyia evansi. This event has epidemiological significance since it affects the infection susceptibility of this sand fly species, which is a proven vector of L. chagasi in Colombian and Venezuelan visceral leishmaniasis foci. Also, it may explain the host seeking behaviour displayed by some partially bloodfed flies found inside houses.

Can the creatinine dialysate-to-plasma ratio from the peritoneal equilibration test be replaced by the sodium dialysate-to-plasma ratio and the sodium level in the dialysate?

The peritoneal equilibration test (PET) is a useful tool that categorizes peritoneal transport. However, the method has some inconveniences. Some authors suggest that measuring the sodium level in the dialysate (NaD) or the dialysate-to-plasma ratio for sodium (D/PNa) can substitute for the PET. We applied a mathematical analysis [Fisher intraclass correlation coefficient (FICC)] to 43 PETs performed in 43 peritoneal dialysis patients (29 males, 14 females) with a mean age of 55.3 years (range: 28-85 years). Determinations of NaD, of sodium level in plasma (NaP), and of D/PNa at times 0, 30, 60, 120, and 240 minutes were added to the usual PET determinations. After using the NaD240 and the D/PNa240 values to calculate the cut-off values for the various peritoneal transport categories, we obtained a transport distribution very similar to that of the PET dialysate-to-plasma ratio for creatinine after 240 minutes (D/PCr240). At the same time, the FICC showed good (0.69) and excellent (0.77) correlation of NaD240 and D/PNa240 respectively with the D/PCr240. Therefore either of these two methods, which are cheaper and quicker than a PET, can be used to categorize peritoneal transport with a high degree of reliability.

The primary care clinic as a setting for continuing medical education: program description

The Mexican Institute of Social Security (IMSS) is Mexico's Largest state-financed health care system, providing care to 50 million people. This system comprises 1450 family medicine clinics staffed by 14,000 family physicians, as well as 240 secondary care hospitals and 10 tertiary care medical centres. We developed a program of continuing medical education (CME) for IMSS family physicians. The program had 4 stages, which were completed over a 7-month period: development of clinical guidelines, training of clinical instructors, an educational intervention (consisting of interactive workshops, individual tutorials and peer group sessions), and evaluation of both physicians' performance and patients' health status. The pilot study was conducted in an IMSS family medicine clinic providing care to 45,000 people; 20 family physicians and 4 clinical instructors participated. The 2 main reasons for visits to IMSS family medicine clinics are acute respiratory infections and type 2 diabetes mellitus. Therefore, patients being treated at the clinic for either of these illnesses were included in the study. The sources of data were interviews with physicians and patients, clinical records and written prescriptions. A 1-group pretest-posttest design was used to compare physicians' performance in treating the 2 illnesses of interest. We found that the daily activities of the clinic could be reorganized to accommodate the CME program and that usual provision of health care services was maintained. Physicians accepted and participated actively in the program, and their performance improved over the course of the study. We conclude that this CME strategy is feasible, is acceptable to family physicians and may improve the quality of health care provided at IMSS primary care facilities. The effectiveness and sustainability of the strategy should be measured through an evaluative study.

Correlated morphologic and genetic diversity among Lutzomyia longipalpis (Diptera: Psychodidae) collections in Venezuela

Diversity among Lutzomyia longipalpis populations in Venezuela was characterized using 2 methods: larval mouthpart morphology-morphometry and isoenzyme electrophoresis. Analysis of the results suggested the presence of 2 morpho-genotypes. The mentum, maxillary comb, mandibular ventral teeth, and adenylate kinase and hexokinase enzyme-encoding loci suggested that a population from the northwestern Coriano System (Curarigua) is a distinct lineage within the L. longipalpis complex. Three widely separated populations from the Llanos (savanna), Andes, and northcentral Coastal Cordillera showed no significant substructure. These studies provide morphologic markers that are congruent with genetic data and suggest that the morphologic markers may be used to characterize and differentiate populations within this species complex.

Genetic divergence among Venezuelan populations of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae)

Lutzomyia longipalpis (Lutz & Neiva) is the primary vector of visceral leishmaniasis in Venezuela. An analysis of alleles at seven enzyme-encoding loci among four populations from different geographic and epidemiological regions revealed strong genetic substructuring. Isozyme analysis indicated that L. longipalpis in Venezuela is a complex of at least two subspecies. Possible differences in population size during their evolutionary histories, varying colonization histories and geological events may explain discrepancies in the patterns of variation observed at genetic markers between these four populations.

Prostate cancer induction in autoimmune rats and modulation of T cell apoptosis

In this study we present an experimental model of prostate gland cancer induced by long term hormonal treatment with testosterone in combination with a chemical carcinogenic agent in male Wistar rats with autoimmune prostatitis (AIP). This system is particularly attractive in order to study the factors involved in the transition from a non-invasive to an invasive carcinoma, decisive in the risk of human cancer. At first, autoimmune prostatitis was induced by immunization in 3 months-old male Wistar rats with autologous accessory glands. Then, rats were treated with continuous intradermal implants of testosterone propionate (TP) and with single doses of the chemical carcinogen 7, 12 dimethylbenz (alpha) anthracene (DMBA) by intraperitoneal injection. Histopathological studies of the prostate gland revealed the presence of pre-malignant lesions, particularly the so-called prostatic intraepithelial neoplasm (PIN) in 50% of animals. Moreover, we observed the development of carcinomas in 50% of treated-animals, which could be histologically discriminated in adenocarcinomas, carcinoma of epidermal origin and undifferentiated carcinoma. In autoimmune rats which did not receive any other treatment, exposure to autoantigens gave rise to an atypical hyperplasia of the prostatic gland which could be attributed to the hyperactive state of the gland. Control groups constituted by autoimmune rats treated with TP or DMBA, and normal rats which were exposed to TP and/or DMBA evidenced the presence of PINs at different degrees, but did not develop carcinomas. Moreover, serum acid phosphatase significantly increased as treatment was accomplished, reaching its maximum levels in animals with carcinoma, in which DNA content, determined by image cytometry, showed to be aneuploid. Finally, we provided biochemical and cytofluorometrical evidence of the induction of apoptosis of spleen T cells in carcinoma-bearing hosts, and to a lesser extent in animals with PIN, but not in autoimmune or normal controls, which could represent an alternative molecular mechanism for explaining host immunosuppression triggered by tumors.

Cytochrome oxidase is decreased in piglet hippocampus following hypoxia-ischemia

We assessed cytochrome oxidase (CytOx) staining in sham-operated control piglets and in piglets subjected to 30 minutes of cerebral hypoxia-ischemia (H-I) plus 4 hours of reperfusion (REP). The 1-day-old piglets were sedated, anesthetized, and ventilated. Cerebral blood flows (CBFs) were quantitated using microspheres. H-I was induced by a combination of phlebotomy and cervical tourniquet; the brain was reperfused for four hours after 30 minutes of H-I. CBF was reduced during ischemia in experimental animals from 42 + 13 to 12 + 5 ml/min/100g. CytOx staining of hippocampal sections from 3 control and 3 experimental animals was compared. The staining of the stratum pyramidale neurons of the same portion of the CA1 sector in a single high power field was assessed in a blinded fashion in 4 corresponding sections from each animal, and graded from 0 = no staining to 3 = heavy staining. The results were compared using one-way analysis of variance. Cells with grade 3 staining were significantly more numerous in controls compared to H-I/REP animals (p = 0.03). There were significantly more cells with no CytOx staining in the experimental animals (p = 0.01). These findings suggest that CytOx staining in newborn piglet CA1 is a reliable method of assessing cell dysfunction after H-I.

Physiological age in Lutzomyia youngi (Diptera: Psychodidae) populations from an endemic area for cutaneous leishmaniasis, Venezuela

Batches of sylvatic females of Lutzomyia youngi (Phlebotominae) captured in a Shannon trap on twelve occasions over one year in a locality where subcutaneous leishmaniasis is endemic, near the city of Trujillo, Venezuela, were used to study: 1) the percentages of parous females according to previously established criteria and 2) the average number of eggs laid spontaneously by isolated females during 7 days after feeding on hamsters. The data on the batches of females captured on nights previous to the rainy period (prepluvial) were compared with those on females captured after the rains (postpluvial). Significant differences were detected by variation analysis for two variables and different number of N, as also were consistent groupings by Duncan's Test for pre- and postpluvial lots of females. The females captured on nights prior to the rainy periods (January-March and August-September) presented higher rates of nulliparity (86-72%) and contained or laid a greater number of eggs (71-67) than those captured after the rains (March-June and November-December) which presented lower rates of nulliparity (60-24%) and a smaller number of eggs (50-30). The rainfall peaks occurred in April and September-October, respectively. It is considered that these differences can be used by epidemiological studies as a means of estimating the physiological age of female populations of L. youngy.

Epidemiology of cutaneous leishmaniasis in Merida, Venezuela. III. Altitudinal distribution, age structure, natural infection and feeding behaviour of sandflies and their relation to the risk of transmission

An entomological survey revealed that the distribution of the Lutzomyia species in Merida, Venezuela, varies with altitude. Of the 21 species encountered, 12 (57%) are known to be anthropophilic. The significance of the predominant man-biting species at any altitude is discussed in terms of the risk of transmission of cutaneous leishmaniasis. The general parous rate (and perhaps the ability of a female sandfly to survive oviposition and transmit Leishmania parasites during a second or subsequent bloodmeal) was found to be related to rainfall and altitude. The finding of Leishmania infections in wild-caught parous females of anthropophilic species indicates the high risk of acquiring leishmaniasis in the study area. Observations on the feeding habits of the sandflies indicate that some species are opportunistic feeders, attracted to a variety of hosts, including man.

Leishmania braziliensis spp. in the nasal mucosa of guinea pigs inoculated in the tarsi

Two lots of 20 young male guinea pigs were inoculated subcutaneously in the tarsi with 10(4) amastigotes of Leishmania braziliensis braziliensis or L. b. guyanensis to study the susceptibility of this Neotropical hystricomorph rodent the autochthonous parasites. Almost 50% of the animals showed lesions in the inoculation site and had parasitizations that were infective to hamsters, as shown by inoculating homogenates of the dermal lesion, of the spleen, of the liver, and of the nasal mucosa into hamsters at 20, 40, 60, and 120 days after inoculation of the guinea pig. Smears of the above organs showed the presence of amastigotes. Parasites inoculated into the tarsi were detected early in the skin, spleen, and liver of the guinea pig host. Blood cultures made by cardiopuncture on sacrifice of the guinea pigs were uniformly negative. The nasal mucosa of nearly all animals positive in the skin or viscera was invaded early by the parasites, although with greater frequency between 60 and 120 days post-inoculation. The use of this model for the study of mucocutaneous parasitism by L. braziliensis is discussed, together with the phenomena of parasitism at a distance from the inoculation site, the temperature of the body regions affected, and the possible genetic influence on susceptibility of the guinea pig to L. braziliensis.

Results of a 400-patient carcinoembryonic antigen second-look colorectal cancer study

Four hundred patients with resectable colon and rectal cancers were operated on by 37 surgeons at 31 institutions. Patients were monitored with carcinoembryonic antigen (CEA) level determinations and clinical examinations. One hundred thirty patients had recurrences, and 75 were reoperated on, with 43 reoperations CEA-directed and 32 clinically directed. Two of 75 died within 1 month after the second operation. Twenty-two second-look patients remain free of disease 5 years after their second operation. The highest resectability of recurrent cancer occurred in patients with a CEA level below 11 ng/ml in whom the CEA level was determined at intervals of 1 to 2 months.

Results of a 400-patient carcinoembryonic antigen second-look colorectal cancer study

Four hundred patients with resectable colon and rectal cancers were operated on by 37 surgeons at 31 institutions. Patients were monitored with carcinoembryonic antigen (CEA) level determinations and clinical examinations. One hundred thirty patients had recurrences, and 75 were reoperated on, with 43 reoperations CEA-directed and 32 clinically directed. Two of 75 died within 1 month after the second operation. Twenty-two second-look patients remain free of disease 5 years after their second operation. The highest resectability of recurrent cancer occurred in patients with a CEA level below 11 ng/ml in whom the CEA level was determined at intervals of 1 to 2 months.