Classics revisited: Miguel Fernández on germ layer inversion and specific polyembryony in armadillos.

BACKGROUND: Miguel Fernández was an Argentinian zoologist who published the first account of obligate polyembryony in armadillos. His contribution is here discussed in relation to his contemporaries, Newman and Patterson, and more recent work. FINDINGS: Fernandez worked on the mulita (Dasypus hybridus). He was able to get early stages before twinning occurred and show it was preceded by inversion of the germ layers. By the primitive streak stage there were separate embryonic shields and partition of the amnion. There was, however, a single exocoelom and all embryos were enclosed in a common set of membranes comprising chorion towards the attachment site in the uterine fundus and inverted yolk sac on the opposite face. He showed that monozygotic twinning did not occur in another armadillo, the peludo (Chaetophractus villosus). CONCLUSIONS: Fernández's work represented a major breakthrough in understanding how twinning occurred in armadillos. His work and that of others is of intrinsic interest to zoologists and has a direct bearing on the origin of monozygotic twins and birth defects in humans.

An unusual feature of yolk sac placentation in Necromys lasiurus (Rodentia, Cricetidae, Sigmodontinae).

We studied the development of the inverted yolk sac in a New World rodent, Necromys lasiurus during early placentation. Ten implantation sites were investigated by means of histology, immunohistochemistry and electron microscopy. The yolk sac was villous near its attachment to the placenta. Elsewhere it was non-villous and closely attached to the uterus. The uterine glands were shallow and wide mouthed. They were associated with vessels and filled with secretion, suggesting the release of histotroph. This feature was absent at later stages. The intimate association of the yolk sac with specialized glandular regions of the uterus may represent a derived character condition of Necromys and/or sigmodont rodents.

Use of mobile phones by medical staff at Queen Elizabeth Hospital, Barbados: evidence for both benefit and harm.

All members of medical staff, including students, were asked to participate in a self-administered questionnaire concerning patterns of mobile phone use and care. Participants' phones were cultured for micro-organisms. Healthcare professionals working in close proximity to sensitive equipment were surveyed concerning adverse events associated with mobile phones. Telephone operators were asked to monitor time elapsed as they attempted to contact medical staff by various methods. Of 266 medical staff and students at the time of the study, 116 completed questionnaires (response rate=44%). Almost all (98%) used mobile phones: 67% used their mobile phones for hospital-related matters; 47% reported using their phone while attending patients. Only 3% reported washing their hands after use and 53% reported never cleaning their phone. In total, 101 mobile phones were cultured for micro-organisms; 45% were culture-positive and 15% grew Gram-negative pathogens. The survey of staff working in close proximity to sensitive equipment revealed only one report of minor interference with life-saving equipment. Telephone operators were able to contact medical staff within 2 min most easily by mobile phone. Mobile phones were used widely by staff and were considered by most participants as a more efficient means of communication. However, microbial contamination is a risk associated with the infrequent cleaning of phones. Hospitals should develop policies to address the hygiene of mobile phones.

Risk behaviour, healthcare access and prevalence of infection with Chlamydia trachomatis and Neisseria gonorrhoeae in a population-based sample of adults in Barbados.

OBJECTIVES: To estimate the prevalence of urogenital infection with Chlamydia trachomatis and Neisseria gonorrhoeae in people 18 to 35 years of age in Barbados, and to examine factors associated with infection. METHODS: Cross-sectional survey of randomly selected people from the voters' register of one electoral district and the collection of urine samples for testing by PCR. RESULTS: The response rate was 82%; 408 people (195 males and 213 females) completed a questionnaire and had their urine collected. 397 urine samples were satisfactorily tested. Prevalence of C trachomatis urogenital infection was 11.3% (95% CI +/-2.9) and N gonorrhoeae 1.8% (95% CI +/-1.2) with 12.6% (95% CI +/-3.1) having either or both infections. The difference in prevalence by gender was not significant. Multivariate logistic regression showed that prevalence of C trachomatis and/or N gonorrhoeae decreased with increasing age (per year OR 0.89, 95% CI 0.84 to 0.96, p = 0.001), and decreasing time (6 months) since last medical consultation (OR 0.44, 95% CI 0.22 to 0.88, p = 0.02). Most (76%) infected people were asymptomatic. Condom use at last intercourse with a partner not being lived with was not protective (reported by 52%, p = 0.617). The usual source of health care was evenly distributed between the public and private sectors and was not associated with infection. Only 30% of people had ever heard of chlamydia, whereas 92% were aware of gonorrhoea. CONCLUSIONS: Asymptomatic infection with C trachomatis is an important reservoir of infection, which will remain undetected unless physicians and young people are made aware of this and screening is introduced.

Trends in the uptake of antenatal voluntary counselling and testing for HIV and HIV prevalence among childbearing women in Barbados, 1993-2004: evidence to gauge the effectiveness of HIV prevention measures.

OBJECTIVES: To describe the long term trends on the uptake of antenatal voluntary counselling and testing (VCT) for Human Immunodeficiency Virus (HIV) and on the HIV prevalence among pregnant women. These data were used to gauge the impact of the National Acquired Immunodeficiency Syndrome (AIDS) Intervention Programme on preventing mother-to-child transmission (PMTCT) in Barbados. METHODS: This was a population based study. Data for this report were drawn from the HIV Surveillance Programme for the mother-to-child transmission of HIV The study population comprised all pregnant women who attended the various antenatal care clinics throughout Barbados during the period between 1993 and 2004. RESULT: The uptake of the VCT for HIV among the pregnant women in Barbados has increased from 39.9% in 1993 to over 89.7% in 2004 (p < 0.0001). Mean annual HIV prevalence decreased from 10.53 per thousand women screened in 1993-1996 to 8.23 during 2001-2004 (p = 0.121). Mean annual incidence rate of newly diagnosed HIV infection among the pregnant women declined from 8.83 per thousand women screened during 1993-1996 to 4.53 per thousand pregnant women screened during 2001-2004 (p = 0.004). Mean annual incidence rate of newly diagnosed HIV infection among the pregnant women aged less than 25 years during the corresponding period declined from 10.17 per thousand women aged less than 25 years screened to 4.75 per thousand women screened (p = 0.003). CONCLUSION: There has been a significant decline in the prevalence and incidence of HIV since the late-1990s. Although new infections are still occurring, the numbers are small. The decline may partly be explained by the impact of PMTCT and the general preventive measures on the spread of HIV among this population.

Placentation in cloned cattle: structure and microvascular architecture.

To elucidate the morphological differences between placentas from normal and cloned cattle pregnancies reaching term, the umbilical cord, placentomes and interplacentomal region of the fetal membranes were examined macroscopically as well as by light and scanning electron microscopy. In pregnancies established by somatic nucleus transfer (NT), the umbilical cord and fetal membranes were edematous. Placentomal fusion was common, resulting in increased size and a decreased number of placentomes. Extensive areas of the chorioallantoic membrane were devoid of placentomes. An increased number of functional or accessory microcotyledons (<1 cm) were present at the maternally oriented surface of fetal membranes. Extensive areas of extravasated maternal blood were present within the placentomes and in the interplacentomal region. The crypts on the caruncular surface were dilated and accommodated complexes of more than one primary villus, as opposed to a single villus in non-cloned placentae. Scanning electron microscopy of blood vessel casts revealed that there was also more than one stem artery per villous tree and that the ramification of the vessels failed to form dense complexes of capillary loops and sinusoidal dilations as in normal pregnancies. At the materno-fetal interface, however, the trophoblast and uterine epithelium had normal histology. In conclusion, the NT placentas had a range of pathomorphological changes; this was likely associated with the poor clinical outcome of NT pregnancies.

Trends in the uptake of antenatal voluntary counselling and testing for HIV and HIV prevalence among childbearing women in Barbados, 1993-2004: evidence to gauge the effectiveness of HIV prevention measures / Tendencias en el interés por el asesoramiento y prueba voluntarios prenatales para el vih, y prevalencia del vih entre las embarazadas de barbados, 1993­2004: evidencia para evaluar la efectividad de las medidas para prevenir el vih

OBJECTIVES: To describe the long term trends on the uptake of antenatal voluntary counselling and testing (VCT) for Human Immunodeficiency Virus (HIV) and on the HIV prevalence among pregnant women. These data were used to gauge the impact of the National Acquired Immunodeficiency Syndrome (AIDS) Intervention Programme on preventing mother-to-child transmission (PMTCT) in Barbados. METHODS: This was a population based study. Data for this report were drawn from the HIV Surveillance Programme for the mother-to-child transmission of HIV The study population comprised all pregnant women who attended the various antenatal care clinics throughout Barbados during the period between 1993 and 2004. RESULT: The uptake of the VCT for HIV among the pregnant women in Barbados has increased from 39.9in 1993 to over 89.7in 2004 (p < 0.0001). Mean annual HIV prevalence decreased from 10.53 per thousand women screened in 1993-1996 to 8.23 during 2001-2004 (p = 0.121). Mean annual incidence rate of newly diagnosed HIV infection among the pregnant women declined from 8.83 per thousand women screened during 1993-1996 to 4.53 per thousand pregnant women screened during 2001-2004 (p = 0.004). Mean annual incidence rate of newly diagnosed HIV infection among the pregnant women aged less than 25 years during the corresponding period declined from 10.17 per thousand women aged less than 25 years screened to 4.75 per thousand women screened (p = 0.003). CONCLUSION: There has been a significant decline in the prevalence and incidence of HIV since the late-1990s. Although new infections are still occurring, the numbers are small. The decline may partly be explained by the impact of PMTCT and the general preventive measures on the spread of HIV among this population.

Objetivos. Describir las tendencias a largo plazo en relación con el interés en el asesoramiento y prueba voluntarios (APV) prenatales para el virus de la inmunodeficiencia humana VIH, así como en relación con la prevalencia del VIH entre las embarazadas. Estos datos fueron usados para evaluar el impacto del Programa Nacional de Intervención del Síndrome de Inmunodeficiencia Adquirida (SIDA) en la prevención de la transmisión de madre a hijo (PTMH) en Barbados. Métodos. Se trató de un estudio poblacional. Los datos para este reporte fueron tomados del Programa de Vigilancia del VIH para la transmisión madre a hijo del VIH. El estudio poblacional abarcó a todas las embarazadas que asistieron a las distintas clínicas de atención prenatal en todo Barbados durante el período comprendido entre 1993 y 2004. Resultado. El interés mostrado por el APV del VIH entre las embarazadas de Barbados, ha aumentado de 39.9% en 1993 a más de 89.7% en 2004 (p < 0.0001). La media anual de prevalencia del VIH disminuyó de 10.53 por cada mil mujeres sometidas a pesquisaje en 1993­1996 a 8.23 durante 2001­2004 (p = 0.121). La tasa de incidencia anual media de infección por VIH de diagnóstico reciente entre las embarazadas descendió de 8.83 por cada mil mujeres embarazadas sometidas a pesquisaje durante 1993­1999 a 4.53 por cada mil mujeres sometidas a pesquisaje durante 2001­2004 (p = 0.004). La tasa de incidencia anual media de infección por VIH de diagnóstico reciente entre las embarazadas menores de 25 años de edad durante el periodo correspondiente disminuyó de 10.17 por cada mil mujeres menores de 25 años de edad sometidas a pesquisaje, a 4.75 por cada mil mujeres sometidas a pesquisaje (p = 0.003). Conclusión. Ha habido un descenso significativo en la prevalencia e incidencia del VIH desde los finales de 1990. Aunque todavía se están produciendo nuevas infecciones, su número es pequeño. El descenso puede explicarse en parte por el impacto del PTMH y las medidas generales de prevención de la difusión del VIH entre esta población

Waiting and interaction times for patients in a developing country accident and emergency department.

OBJECTIVE: To determine the interaction and waiting times of patients in Barbados Queen Elizabeth Hospital Accident and Emergency Department (A&E), identify their determinants, and compare them to international benchmarks. METHODS: Trained research assistants monitored all patients attending A&E during a one week period in 2003. The time in and out of each step in the process of care was recorded along with demographic data, diagnosis, and acuity. Time elapsed was calculated for various steps in care and compared to international benchmarks. Determinants of timely care were identified. RESULTS: Of 882 eligible A&E patients, 675 (77%) had accurate data and were entered into the study. Interaction times were short, with median total interaction time 13 (IQR 9-21) minutes. Waiting times were long ranging from median 6.5 (IQR 2-22) minutes for registration to 213 (IQR 154-316) minutes for lab results. Of concern was a median wait of 10 (IQR 2-46) minutes for triage and 178 (IQR 105-305) minutes to be seen by a doctor. Mean total length of stay was 377 (SD 261) minutes compared to US benchmark of 90 minutes. All other waiting times were at least twice US benchmarks. Paediatrics cases and children aged 0-11 years had the shortest waiting times and length of stay, whereas medicine patients and those over 49 years had the longest. Those with highest acuity had the shortest waiting times and length of stay. CONCLUSIONS: The A&E could improve patient care processes by shortening waiting times, especially for laboratory results, triage, and seeing a doctor, particularly for older medicine patients.

Immunological and virological responses to highly active antiretroviral therapy in a non-clinical trial setting in a developing Caribbean country.

OBJECTIVE: Few data exist on the efficacy of antiretroviral therapy in individuals infected with HIV in the Caribbean. We evaluated the virological and immunological responses of HIV-infected adults starting highly active antiretroviral therapy (HAART). DESIGN: This was a prospective observational cohort study. METHODS: A total of 158 antiretroviral-naive patients who initiated HAART between January 2002 and March 2003, and completed at least 6 months of treatment and follow up, were included in the analysis. The response to therapy was assessed by changes in CD4 cell counts and viral loads from baseline. The mean increase in CD4 cell count, the rate of virological success (a viral load of <50 HIV-1 RNA copies/mL) and the rate of immunological success (an increase in CD4 cell count of > or =50 cells/microL over the baseline value) after commencing HAART were measured. RESULTS: In total, 82% of patients (123 of 150) achieved viral loads of <50 copies/mL after 6 months of therapy. Viral success rate after 6 months of HAART was similar irrespective of gender, pre-HAART CD4 cell count and pre-HAART viral load. However, patients older than 40 years were significantly more likely to achieve virological success than those younger than 40 years. At 6 months after starting HAART, 79.5% of patients were estimated to have achieved immunological success and 17.9% had an increase in CD4 cell count of > or =200 cells/microL over the baseline value. The median increase in CD4 cell count for the 156 patients who had CD4 cell counts at baseline and at 6 months of therapy was 122 cells/microL. CONCLUSION: In this cohort of antiretroviral-naive HIV-infected adults, there was a high rate of virological and immunological success after 6 months of HAART, irrespective of the pre-HAART viral load and CD4 cell count.

Placentation in the rock cavy, Kerodon rupestris (Wied).

Rock cavies are rodents found in the semi-arid caatinga of Brazil. We studied the structure of the rock cavy placenta by light and transmission electron microscopy. The exchange area of the labyrinth was organized in lobes separated by interlobular areas. The interhaemal barrier was syncytial haemomonochorial. The syncytiotrophoblast had recesses in the basal membrane and some invaginations of the apical membrane, but transtrophoblastic channels could not be found. The interlobular regions comprised syncytiotrophoblast, enclosing maternal venous blood channels, and cytotrophoblast. There was a prominent subplacenta composed of cytotrophoblast and syncytiotrophoblast. Microvilli projected into spaces between the cytotrophoblasts and into lacunae within the syncytiotrophoblast. The yolk sac epithelium exhibited coated pits, endocytotic vesicles and larger vacuoles, consistent with a role in protein uptake from the uterine lumen. Tight junctions between these cells provided a barrier to diffusion by the intercellular route. The reproductive biology of the rock cavy differs from other members of the family, including the guinea pig, but the architecture of the placenta remains remarkably constant.

Vascular organization of the hystricomorph placenta: a comparative study in the agouti, capybara, guinea pig, paca and rock cavy.

The placental vasculature of five hystricomorph rodents was examined by latex injection of the blood vessels, immunohistochemistry and scanning electron microscopy of vessel casts. The pattern of branching of the vessels is described at the level of fine structure. The placenta is divided into lobes separated by interlobular trophoblast. Fetal arteries course through the interlobular areas and give rise to capillaries from which blood drains into veins at the centre of the lobes. Maternal blood reaches the placenta through spiral arteries that pass around the perimeter of the subplacenta. They supply large maternal blood sinuses, lined by trophoblast, which run through the interlobular areas and into the centre of the lobes. Here they supply fine channels that run parallel to the fetal capillaries, so that maternal blood flows from the centre of the lobe to the periphery. This arrangement provides the morphological basis for countercurrent exchange. The maternal channels of the labyrinth drain into spaces formed by the latticework of the interlobular trophoblast and thence through venous lacunae to a basal venous lacunar ring. The subplacenta is supplied by a single fetal artery. The vessels within the subplacenta pursue a tortuous course with dilatations and constrictions as in an endocrine gland.

Placentation in the capybara (Hydrochaerus hydrochaeris), Agouti (Dasyprocta aguti) and paca (Agouti paca).

Placentae of three hystricimorph rodents--capybara, agouti and paca--were examined by conventional histology, immunohistochemistry for cytokeratin and vimentin, and TUNEL staining. The placentae were divided into lobules of labyrinthine syncytium separated by interlobular and marginal trophoblast. The subplacenta comprised cytotrophoblasts, supported on lamellae of allantoic mesoderm, and syncytiotrophoblast. The central excavation was still apparent in the definitive placenta of capybara. In agouti and paca, the decidua of the junctional zone formed a mesoplacenta comprising a capsule and a pedicle. Towards term the pedicle formed a tenuous attachment between placenta and uterine wall comprising a few maternal vessels surrounded by degraded tissue. In paca placenta, it was shown by TUNEL staining that breakdown of this tissue occurred by apoptosis. The visceral yolk sac was highly villous and, in agouti, the yolk sac villi were extremely long. Lateral to its attachment to the placenta, the fetal surface was covered with non-vascular yolk sac endoderm. A layer of spongiotrophoblast cells was interposed between the endoderm and the marginal trophoblast.