In vitro recordings of human neocortical oscillations.

Electrophysiological oscillations are thought to create temporal windows of communication between brain regions. We show here that human cortical slices maintained in vitro can generate oscillations similar to those observed in vivo. We have characterized these oscillations using local field potential and whole-cell recordings obtained from neocortical slices acquired during epilepsy surgery. We confirmed that such neocortical slices maintain the necessary cellular and circuitry components, and in particular inhibitory mechanisms, to manifest oscillatory activity when exposed to glutamatergic and cholinergic agonists. The generation of oscillations was dependent on intact synaptic activity and muscarinic receptors. Such oscillations differed in electrographic and pharmacological properties from epileptiform activity. Two types of activity, theta oscillations and high gamma activity, uniquely characterized this model-activity not typically observed in animal cortical slices. We observed theta oscillations to be synchronous across cortical laminae suggesting a novel role of theta as a substrate for interlaminar communication. As well, we observed cross-frequency coupling (CFC) between theta phase and high gamma amplitude similar to that observed in vivo. The high gamma "bursts" generated by such CFC varied in their frequency content, suggesting that this variability may underlie the broadband nature of high gamma activity.

Hypoglycemia-induced alterations in hippocampal intrinsic rhythms: Decreased inhibition, increased excitation, seizures and spreading depression.

UNLABELLED: Seizures are the most common clinical presentation of severe hypoglycemia, usually as a side effect of insulin treatment for juvenile onset type 1 diabetes mellitus and advanced type 2 diabetes. We used the mouse thick hippocampal slice preparation to study the pathophysiology of hypoglycemia-induced seizures and the effects of severe glucose depletion on the isolated hippocampal rhythms from the CA3 circuitry. METHODS AND RESULTS: Dropping the glucose perfusate concentration from the standard 10 mM to 1 mM produced epileptiform activity in 14/16 of the slices. Seizure-like events (SLEs) originated in the CA3 region and then spread into the CA1 region. Following the SLE, a spreading-depression (SD)-like event occurred (12/16 slices) with irreversible synaptic failure in the CA1 region (8/12 slices). CA3 SD-like events followed ~30 s after the SD-like event in the CA1 region. Less commonly, SD-like events originated in the CA3 region (4/12). Additionally, prior to the onset of the SLE in the CA3 area, there was decreased GABA correlated baseline SPW activity (bSPW), while there was increased large-amplitude sharp wave (LASW) activity, thought to originate from synchronous pyramidal cell firing. CA3 pyramidal cells displayed progressive tonic depolarization prior to the seizure which was resistant to synaptic transmission blockade. The initiation of hypoglycemic seizures and SD was prevented by AMPA/kainate or NMDA receptor blockade. CONCLUSIONS: Severe glucose depletion induces rapid changes initiated in the intrinsic CA3 rhythms of the hippocampus including depressed inhibition and enhanced excitation, which may underlie the mechanisms of seizure generation and delayed spreading depression.

High frequency of endoluminal thrombus in patients with ischaemic stroke following AARS-CoV-2 infection.

BACKGROUND: Ischaemic stroke may be a major complication of SARS-CoV-2 infection. Studying and characterising the different aetiological subtypes, clinical characteristics, and functional outcomes may be valuable in guiding patient selection for optimal management and treatment. METHODS: Data were collected retrospectively on consecutive patients with COVID-19 who developed acute focal brain ischaemia (between 1 March and 19 April 2020) at a tertiary university hospital in Madrid (Spain). RESULTS: During the study period, 1594 patients were diagnosed with COVID-19. We found 22 patients with ischaemic stroke (1.38%), 6 of whom did not meet the inclusion criteria. The remaining 16 patients were included in the study (15 cases of ischaemic stroke and one case of transient ischaemic attack). Median baseline National Institutes of Health Stroke Scale score was 9 (interquartile range: 16), and mean (standard deviation) age was 73 years (12.8). Twelve patients (75%) were men. Mean time from COVID-19 symptom onset to stroke onset was 13 days. Large vessel occlusion was identified in 12 patients (75%). We detected elevated levels of D-dimer in 87.5% of patients and C-reactive protein in 81.2%. The main aetiology was atherothrombotic stroke (9 patients, 56.3%), with the predominant subtype being endoluminal thrombus (5 patients, 31.2%), involving the internal carotid artery in 4 cases and the aortic arch in one. The mortality rate in our series was 44% (7 of 16 patients). CONCLUSIONS: In patients with COVID-19, the most frequent stroke aetiology was atherothrombosis, with a high proportion of endoluminal thrombus (31.2% of patients). Our clinical and laboratory data support COVID-19-associated coagulopathy as a relevant pathophysiological mechanism for ischaemic stroke in these patients.

High frequency of endoluminal thrombus in patients with ischaemic stroke following SARS-CoV-2 infection. / Alta frecuencia de trombo endoluminal en pacientes con ictus isquémico tras la infección por coronavirus 2019.

BACKGROUND: Ischaemic stroke may be a major complication of SARS-CoV-2 infection. Studying and characterising the different aetiological subtypes, clinical characteristics, and functional outcomes may be valuable in guiding patient selection for optimal management and treatment. METHODS: Data were collected retrospectively on consecutive patients with SARS-CoV-2 infection who developed acute focal brain ischaemia (between 1 March and 19 April 2020) at a tertiary university hospital in Madrid (Spain). RESULTS: During the study period, 1594 patients were diagnosed with COVID-19. We found 22 patients with ischaemic stroke (1.38%), 6 of whom did not meet the inclusion criteria. The remaining 16 patients were included in the study (15 cases of ischaemic stroke and one case of transient ischaemic attack). Median baseline National Institutes of Health Stroke Scale score was 9 (interquartile range: 16), and mean (standard deviation) age was 73 years (12.8). Twelve patients (75%) were men. Mean time from COVID-19 symptom onset to stroke onset was 13 days. Large vessel occlusion was identified in 12 patients (75%). We detected elevated levels of D-dimer in 87.5% of patients and C-reactive protein in 81.2%. The main aetiology was atherothrombotic stroke (9 patients, 56.3%), with the predominant subtype being endoluminal thrombus (5 patients, 31.2%), involving the internal carotid artery in 4 cases and the aortic arch in one. The mortality rate in our series was 44% (7 of 16 patients). CONCLUSIONS: In patients with COVID-19, the most frequent stroke aetiology was atherothrombosis, with a high proportion of endoluminal thrombus (31.2% of patients). Our clinical and laboratory data support COVID-19-associated coagulopathy as a relevant pathophysiological mechanism for ischaemic stroke in these patients.

Alta frecuencia de trombo endoluminal en pacientes con ictus isquémico tras la infección por coronavirus 2019 / High frequency of endoluminal thrombus in patients with ischaemic stroke following SARS-CoV-2 infection

Introducción El ictus isquémico puede ser una complicación grave en los pacientes con infección por SARS-CoV-2. Estudiar y caracterizar los diferentes subtipos etiológicos, las características clínicas y el pronóstico funcional podrá resultar útil en la selección de pacientes para un manejo y tratamiento óptimos. Métodos La recogida de variables se hizo de forma retrospectiva en pacientes consecutivos con infección por SARS-CoV-2 que desarrollaron un episodio de isquemia cerebral focal (entre el 1 de marzo del 2020 y el 19 de abril del 2020). Se llevó a cabo en un hospital universitario de tercer nivel en la Comunidad de Madrid (España). Resultados Durante el período de estudio 1.594 pacientes fueron diagnosticados de infección por SARS-CoV-2. Identificamos a 22 pacientes con ictus isquémico (1,38%); de estos, no cumplieron los criterios de inclusión 6. Un total de 16 pacientes con isquemia cerebral focal constituyeron la serie del estudio (15 con ictus isquémico y uno con accidente isquémico transitorio). En la valoración basal en el National Institutes of Health Stroke Scale la mediana fue de 9 (rango intercuartil: 16), la edad media ± desviación estándar fue de 73 ± 12,8 años; 12 pacientes fueron varones (75%). El tiempo desde los síntomas de COVID-19 hasta el ictus fue de 13 días. Se encontró oclusión de gran vaso en 12 pacientes (75%). El dímero-D estuvo elevado en el 87,5% y la proteína C reactiva en el 81,2% de los casos. La etiología más frecuente del ictus isquémico fue la aterotrombosis (9 pacientes, 56,3%) con un subtipo predominante que fue el trombo endoluminal sobre placa de ateroma (5 pacientes, 31,2%), 4 de ellos en la arteria carótida interna y uno de ellos en el arco aórtico. La mortalidad en nuestra serie fue del 44% (7 de 16 pacientes). Conclusiones En los pacientes con ictus y COVID-19 la etiología más frecuente fue la aterotrombótica, con una elevada frecuencia de trombo endoluminal sobre placa de ateroma... (AU)

Background Ischaemic stroke may be a major complication of SARS-CoV-2 infection. Studying and characterising the different aetiological subtypes, clinical characteristics, and functional outcomes may be valuable in guiding patient selection for optimal management and treatment. Methods Data were collected retrospectively on consecutive patients with SARS-CoV-2 infection who developed acute focal brain ischaemia (between 1 March and 19 April 2020) at a tertiary university hospital in Madrid (Spain). Results During the study period, 1594 patients were diagnosed with COVID-19. We found 22 patients with ischaemic stroke (1.38%), 6 of whom did not meet the inclusion criteria. The remaining 16 patients were included in the study (15 cases of ischaemic stroke and one case of transient ischaemic attack). Median baseline National Institutes of Health Stroke Scale score was 9 (interquartile range: 16), and mean (standard deviation) age was 73 years (12.8). Twelve patients (75%) were men. Mean time from COVID-19 symptom onset to stroke onset was 13 days. Large vessel occlusion was identified in 12 patients (75%). We detected elevated levels of D-dimer in 87.5% of patients and C-reactive protein in 81.2%. The main aetiology was atherothrombotic stroke (9 patients, 56.3%), with the predominant subtype being endoluminal thrombus (5 patients, 31.2%), involving the internal carotid artery in 4 cases and the aortic arch in one. The mortality rate in our series was 44% (7 of 16 patients). Conclusions In patients with COVID-19, the most frequent stroke aetiology was atherothrombosis, with a high proportion of endoluminal thrombus (31.2% of patients). Our clinical and laboratory data support COVID-19–associated coagulopathy as a relevant pathophysiological mechanism for ischaemic stroke in these patients. (AU)

Alta frecuencia de trombo endoluminal en pacientes con ictus isquémico tras la infección por coronavirus 2019 / High frequency of endoluminal thrombus in patients with ischaemic stroke following SARS-CoV-2 infection

Introducción El ictus isquémico puede ser una complicación grave en los pacientes con infección por SARS-CoV-2. Estudiar y caracterizar los diferentes subtipos etiológicos, las características clínicas y el pronóstico funcional podrá resultar útil en la selección de pacientes para un manejo y tratamiento óptimos. Métodos La recogida de variables se hizo de forma retrospectiva en pacientes consecutivos con infección por SARS-CoV-2 que desarrollaron un episodio de isquemia cerebral focal (entre el 1 de marzo del 2020 y el 19 de abril del 2020). Se llevó a cabo en un hospital universitario de tercer nivel en la Comunidad de Madrid (España). Resultados Durante el período de estudio 1.594 pacientes fueron diagnosticados de infección por SARS-CoV-2. Identificamos a 22 pacientes con ictus isquémico (1,38%); de estos, no cumplieron los criterios de inclusión 6. Un total de 16 pacientes con isquemia cerebral focal constituyeron la serie del estudio (15 con ictus isquémico y uno con accidente isquémico transitorio). En la valoración basal en el National Institutes of Health Stroke Scale la mediana fue de 9 (rango intercuartil: 16), la edad media ± desviación estándar fue de 73 ± 12,8 años; 12 pacientes fueron varones (75%). El tiempo desde los síntomas de COVID-19 hasta el ictus fue de 13 días. Se encontró oclusión de gran vaso en 12 pacientes (75%). El dímero-D estuvo elevado en el 87,5% y la proteína C reactiva en el 81,2% de los casos. La etiología más frecuente del ictus isquémico fue la aterotrombosis (9 pacientes, 56,3%) con un subtipo predominante que fue el trombo endoluminal sobre placa de ateroma (5 pacientes, 31,2%), 4 de ellos en la arteria carótida interna y uno de ellos en el arco aórtico. La mortalidad en nuestra serie fue del 44% (7 de 16 pacientes). Conclusiones En los pacientes con ictus y COVID-19 la etiología más frecuente fue la aterotrombótica, con una elevada frecuencia de trombo endoluminal sobre placa de ateroma... (AU)

Background Ischaemic stroke may be a major complication of SARS-CoV-2 infection. Studying and characterising the different aetiological subtypes, clinical characteristics, and functional outcomes may be valuable in guiding patient selection for optimal management and treatment. Methods Data were collected retrospectively on consecutive patients with SARS-CoV-2 infection who developed acute focal brain ischaemia (between 1 March and 19 April 2020) at a tertiary university hospital in Madrid (Spain). Results During the study period, 1594 patients were diagnosed with COVID-19. We found 22 patients with ischaemic stroke (1.38%), 6 of whom did not meet the inclusion criteria. The remaining 16 patients were included in the study (15 cases of ischaemic stroke and one case of transient ischaemic attack). Median baseline National Institutes of Health Stroke Scale score was 9 (interquartile range: 16), and mean (standard deviation) age was 73 years (12.8). Twelve patients (75%) were men. Mean time from COVID-19 symptom onset to stroke onset was 13 days. Large vessel occlusion was identified in 12 patients (75%). We detected elevated levels of D-dimer in 87.5% of patients and C-reactive protein in 81.2%. The main aetiology was atherothrombotic stroke (9 patients, 56.3%), with the predominant subtype being endoluminal thrombus (5 patients, 31.2%), involving the internal carotid artery in 4 cases and the aortic arch in one. The mortality rate in our series was 44% (7 of 16 patients). Conclusions In patients with COVID-19, the most frequent stroke aetiology was atherothrombosis, with a high proportion of endoluminal thrombus (31.2% of patients). Our clinical and laboratory data support COVID-19–associated coagulopathy as a relevant pathophysiological mechanism for ischaemic stroke in these patients. (AU)

Biological affinities and regional microevolution among pre-Hispanic communities of Colombia's Northern Andes.

Dental non-metric data were used to examine the biological continuity of pre-Hispanic peoples of Colombia's Northern Andes, including highland, lowland and coastal peoples. This report contributes to studies regarding the peopling of South America by establishing a benchmark comparison that includes pre-Hispanic populations of the Northern Andes. The sample consisted of a total of 583 individuals from 56 cemeteries ranging in time from the Early Holocene (10,000 BP) to the Final Late Holocene (500 BP). Permanent dentitions from individuals between 5 and 40 years of age were scored for 87 dental traits based on the ASUDAS. A divergence matrix was programmed using the Smith's Mean Measure of Divergence equation (MMD). Bartlett's adjustment and Ascombe transformation were considered into MMD calculations. Principal Coordenate analysis was applied based on MMD matrix scores. A clear group was found that associated Initial Late Holocene samples with Final Late Holocene samples. Early Holocene samples are very different to that, and Middle Holocene samples show as morphologically intermediate series. A comparison of the frequencies by time and period showed that a limited biological continuity existed. Interbreeding among initial populations of the same regions is expressed in similar frequencies of dental traits within Early Holocene and Middle Holocene samples. Early Holocene samples did not match with Sinodont pattern according to discriminant function analysis. These findings help us to better understand the settlement process of human groups in the Northern Andes and its relationship with migratory movements in South America.

Efficiency of tranexamic acid in perioperative blood loss in hip arthroplasty: a systematic literature review and meta-analysis.

INTRODUCTION AND OBJECTIVE: Tranexamic acid (TXA) is an antifibrinolytic drug used to reduce bleeding in mortality risk situations such as trauma. Our objective was to conduct a systematic literature review to evaluate the effectiveness and safety of TXA in reducing bleeding in hip arthroplasty. MATERIAL AND METHODS: A systematic literature review and meta-analysis of primary studies similar to controlled trials was performed. Literature was searched in MEDLINE, Embase, Cochrane, LILACS, SciELO and Google Scholar. The review was proposed and undertaken by 2 reviewers and the inclusion criteria were: a) patients undergoing arthroplasty for primary unilateral hip replacement; b) comparison of a treatment group with TXA to a control group that received a placebo or no treatment at all, and c) outcome measures, total blood loss, number of patients receiving allogeneic transfusion and/or incidence of thromboembolic complications. The search was restricted to studies published from 1966 to June 2013. RESULTS: A total of 16 studies with 246 patients were retrieved for this review. The total blood loss outcome evidenced a weighted mean difference in favor of TXA vs. controls undergoing hip arthroplasty (-0.45 [P<0.001, 95% CI -0.65 to -0.24]). Weighted relative risk was estimated for the allogeneic transfusion requirement outcome, showing a trend in favor the TXA arm, with fewer patients requiring allogeneic transfusion in hip surgery (0.8 [P<0.02, 95% CI 0.57 to 1.11]); however, this trend was not statistically significant. LIMITATIONS: There is a noticeable difference in methods for quantifying total blood loss across the studies reviewed. The need for transfusion outcomes are probably not significant taking into account the number of events in the TXA group. CONCLUSIONS: TXA can be routinely used to reduce intra- and post-operative blood loss in primary hip arthroplasty.

[The clinical importance of bacteremia during tonsillectomy]. / Importancia clínica de la bacteremia durante la amigdalectomía.

INTRODUCTION: Post-tonsillectomy bacteraemia is a well recognized aetiological factor in streptococcal endocarditis. Prophylactic penicillin has been recommended to reduce its incidence in susceptible patients undergoing tonsillectomy. Recent studies have shown a change in the microflora and an increase in the number of penicillin-resistant organisms in the tonsils of patients undergoing tonsillectomy. OBJECTIVE: The aim of this study was to assess the incidence of post-tonsillectomy bacteraemia, identify the associated organisms, and review the suitability of penicillin in prophylactic regimens. MATERIAL AND METHODS: 102 children were included. Blood culture samples were taken after removal of the first tonsil, which was randomly electrodissected or blunt dissected. Statistical analysis was performed using ANOVA. RESULTS: Of the 102 patients included in the study, 41 (40.1%) had positive post-tonsillectomy blood cultures. Haemophilus influenzae was isolated from 23 (56%) of the positive cultures and Streptococcus viridans from 15 (36.5%). Twenty-five percent of H. influenzae and 50% of the viridans group produced beta-lactamase. CONCLUSIONS: A beta-lactamase stable antibiotic would be more appropriate than penicillin for prophylaxis during tonsillectomy.

Associação à positividade da Lawsonia intracellularis com a expressão clínico-patológica da infecção em suínos da região metropolitana de Bucaramanga (Santander, Colômbia) / Association to positivity of Lawsonia intracellularis with the clinical and pathologic expression of infection in swine from the metropolitan area of Bucaramanga (Santander, Colombia)

Porções de íleo terminal foram coletados de 100 suínos com sinais de doença gastrointestinal na área metropolitana de Bucaramanga, a fim de se estudar a eficiência do diagnóstico de enteropatia proliferativa suína (PPE) pela técnica de PCR aninha (PCRa) empregando sequências específicas (primers) para L. intracellularis: 16S ARN região (270pb) e sua correlação com achados clínicos e patológicos. Todas as amostras foram processadas para se determinar a associação entre positividade por PCR, os sinais clínicos, os achados de necropsia e as lesões histológicas. Cinquenta e seis por cento das amostras foram positivas para L. intracellularis pela PCRa. Só 2% exibiram resultados positivos pela técnica Warthin-Starry. Trinta e um de 100 animais com sinais de anorexia resultaram positivos para PCRa (P>0,05). Não houve associação (P<0,05) entre diarreia e queda no crescimento, bem como associação (P<0,05) entre achados anatomopatológicos e histológicos com PCRa positivas.(AU)

Fragments of terminal ileum were collected from 100 pigs at slaughter from Bucaramanga Metropolitan Area (Santander, Colombia), to study the efficacy of the diagnosis of porcine proliferative enterophaty (PPE) through the technique of nested polymerase chain reaction (PCRa), employing specific sequences (primers) for L. intracellularis: 16S ARN region (270pb) and his correlation with clinic and pathological findings. All samples were processed by standard histological methods and stained with a Warthin-Starry technique. All samples were processed to determinate the association between positive PCRa results, clinical signs and necropsy findings. 56% of the 100 samples were positive for L. intracellularis through PCRa technic. Only 2% exhibited positive results through Warthin-Starry technique. A total of 31 (100) animals with anorexic symptoms were associated with positive results from PCRa (P>,05). No associations (P<0.05) were observed between diarrhea and delayed growth. No associations (P<0.05) were observed between anatomopathological and histological findings with positive PCRa.(AU)

Occurrence of the Uto-Aztecan premolar trait in a contemporary Colombian Amerindian population.

In 2009, in the Indian Kamëntsa community in southern Colombia an oral inspection was conducted on 61 young people. Using the methods of Arizona State University's Dental Anthropology System (ASUDAS) the presence of unilateral Uto-Aztecan premolar (UAP) is reported here.

Bilateral asymmetry in permanent dentition of 13 pre-conquest samples from Argentina (South America).

Bilateral asymmetry is an important field of study in anthropology. The evaluation of bilateral asymmetry of 44 dental non-metric traits of permanent dentition is carried out in this study on 376 adult skulls from different archaeological sites in Argentina (South America). From a total of 44 traits studied, just 12 (27% of the total traits expressed) presented Bilateral Index (BI) values lower than 100% (between 92% and 99%). Results suggest that the expression of all dental traits is probably bilateral. These results show the importance of analysis of bilateral asymmetry for assignment of taxonomic and population value of non-metric dental traits.

[High-fertility groups in Colombia, 1990]. / Los grupos de alta fecundidad en Colombia, 1990.

PIP: Data from the 1990 Demographic and Health Survey (DHS), the 1985 census, and PROFAMILIA and Ministry of Health service statistics were used to analyze persistence of high fertility in different subregions and socioeconomic groups of Colombia. The 1990 DHS sample design divided the country into 13 subregions, allowing greater than usual disaggregation of data. The analytic strategy had three parts: identification of regions exhibiting high fertility during 1987-90; characterization of the regions according to macro level indicators and fertility level; and analysis of the importance of the effects of the contextual and individual variables on recent fertility by means of a multilevel multivariate model. The characterization of the regions and the multivariate analysis tested the hypothesis that contextual conditions influence fertility directly and not just as instruments of the individual characteristics of local populations. Based on demographic transition theory and available information, several contextual indicators were studied: women's status, economic role of children, infant mortality, access to modern family planning methods, and urbanization. The analysis demonstrated the existence of high fertility in 3 of the 13 geographic subregions: northeast, northwest, and Tolima Grande. The characterization of the subregions indicated that those where women had lower status, and where there was less emphasis on children's school attendance, high infant mortality, low access to family planning, and low level of urbanization were not necessarily the areas with the highest total fertility rates, suggesting that a cultural effect might also be present. The northeast and northwest subregions have cultural values and family structures different from those of the rest of Colombia and similar to other Caribbean countries: prevalence of consensual unions, early marriage, and high value of children in the household. The results of the multivariate analysis also indicated the presence of a distinct cultural effect on fertility.^ieng

Transnational criminal organizations and drug trafficking.

Transnational criminal organizations, particularly drug-trafficking organizations, operate unrestricted across international borders. They are very similar in kind to legitimate transnational corporations in structure, strength, size, geographical range and scope of their operations. Above all other features they engage in unregulated forms of capitalist enterprise. To fully understand transnational criminal organizations it is necessary to examine them as organizations responding to economic opportunities and focus on the factors that influence their emergence. Those factors can be understood as a result of the confluence of opportunities, pressures, incentives and resources at the global and national level. The present article identifies the key environmental factors relevant to the emergence of transnational criminal organizations, and explores the intrinsic relationship between those organizations, their home States and host States. It is those conditions which not only give rise to transnational criminal organizations, but also help to sustain them.

Women's status and infant mortality in rural Colombia.

This paper investigates the effects of maternal demographic characteristics and social and economic statuses on infant mortality in rural Colombia. Demographic characteristics include the age of the mother, parity and length of preceding interbirth interval, and sex of infant. Measures of women's status at the time of birth include education, wage labor and occupation, economic stratum, place of residence, and whether the mother is living with a husband. The life history data for the study (involving 4,928 births) were collected in 1986 from a representative sample of two cohorts of women resident in rural central Colombia. Overall differentials in infant mortality by measures of women's status are small and are in good part associated with the differing reproductive behaviors of the women and variations in breastfeeding practices. The sharp declines in infant mortality recorded in rural Colombia in recent years appear less related to improved status of women than to reductions in fertility that enhance infant survivorship and to public health interventions shared by all segments of the population.

PIP: As part of the demographic transition that has been unfolding in Colombia over the last 5 decades, both urban and rural areas have experienced substantial declines in infant mortality. This decline is generally attributed to extensive countrywide health campaigns during the 1950s and 60s aimed at the prevention of disease, government-supported child immunization campaigns during the 1970s and 80s, and improvements in the population's educational level. To investigate the dynamics behind the sharp decline in infant mortality, life history data were collected in 1986 from a representative sample of 2 cohorts of women living in rural central Colombia. 4928 births were available for analysis. The cohorts included women born in 1937-46, who were of reproductive age in the early 1960s when fertility began its decline, or 1955-61, who entered their reproductive period in the 1980s after the sharp decline in fertility. Measures of women's status and demographic characteristics at the time of each birth were reconstructed for the analysis. A total of 207 children born to the study subjects died before their 1st birthday, yielding a 0.042 probability of infant death. Substantial declines in this probability were observed over time, with 0.072 of infants born before 1960 dying compared to 0.050 of those born in 1960-72 and 0.033 of infants born after 1972. Logit model analysis of the life history data indicated that changes in the status of women, including educational attainment, have had only a slight impact on the sharp declines in infant mortality in rural Colombia. More important have been reductions in fertility that have cut the number of high parity and closely spaced births and the prevalence of breastfeeding among rural mothers.

Susceptibilities of 55 strains of Neisseria meningitidis isolated in Spain in 1993 and 1994.

The in vitro susceptibility of 55 strains of Neisseria meningitidis isolated in 1993 and 1994 at the Valme and Macarena Hospitals, Sevilla, Spain to penicillin, ampicillin, cefotaxime, cefpodoxime, imipenem, rifampin, ciprofloxacin, chloramphenicol, tetracycline, erythromycin and trimethoprim-sulfamethoxazole were determined by a microdilution method in Mueller-Hinton broth. Among our N. meningitidis isolates, 36.4% were found to be moderately resistant to penicillin, 43.6% were resistant to trimethoprim/sulfamethoxazole. All the strains were susceptible to tetracycline, ciprofloxacin, cefotaxime and rifampin.

[Forms of population mobility in Bogota and its impact on metropolitan area dynamics: methodology of a survey system]. / Las formas de movilidad de la poblacion de Bogota y su impacto sobre la dinamica del area metropolitana: metodologia de un sistema de encuestas.

PIP: The authors discuss the methodology of a project that aimed to improve knowledge of the dynamics of the population of Bogota, Colombia, and particularly of the spatial mobility of the population and changes in different areas of the metropolitan region.^ieng