Jorge Rey de Castro

Primary and Secondary Infections of Macaca fascicularis Monkeys with Asian and American Genotypes of Dengue Virus 2

ABSTRACT The goal of this study was to compare the immune response and the protection capacity induced by the dengue virus 2 (DENV-2) American and Asian genotypes in Macaca fascicularis monkeys. Animals were infected with American or Asian DENV-2 strains and challenged 1 year later with a DENV-2 Asian genotype strain. The viremia and monkey antibody levels were similar for the different strains after primary and secondary infection; however, the functionality of the antibody response was different. A limited viral replication was demonstrated after the secondary infection in all the monkeys. No virus was isolated in tissue culture, while reverse transcription-PCR showed a late positive reaction in four of five challenged monkeys. The immunoglobulin M response pattern and the detection of antibodies to specific proteins by Western blotting supported the protection data. Despite the demonstration of the protective effect after homologous challenge, a strong anamnestic antibody response was observed.

Viremia and antibody response in green monkeys (Chlorocebus aethiops sabaeus) infected with dengue virus type 2: A potential model for vaccine testing

The increasingly limited availability and high cost of the hitherto most commonly used monkey species in dengue vaccine research has augmented the importance of identifying alternative suitable models for these studies. In this study we examined the capacity of green monkeys (Chlorocebus aethiops sabaeus) to develop dengue viremia, and thus provide a potential model for dengue vaccine testing. Monkeys were inoculated with two different doses of dengue virus type 2. All animals in both groups became viremic after inoculation of the virus. In the lower dose group, mean viremia duration of 5.66 days was detected, whereas in the group that received the 106 PFU dose, viremia had a mean duration of only 1.66 days. Antibody titers were similar to those obtained in previous experiments with rhesus and cynomolgus macaques. We conclude that green monkeys develop viremia and antibody responses and therefore provide a potential model for the preclinical evaluation of novel candidates for dengue vaccines.

Antigen dose escalation study of a VEGF-based therapeutic cancer vaccine in non human primates

CIGB-247 is a cancer therapeutic, based on recombinant modified human vascular endothelial growth factor (VEGF) as antigen, in combination with the oil free adjuvant VSSP (very small sized proteoliposomes of Neisseria meningitidis outer membrane). Our previous experimental studies in mice with CIGB-247 have shown that the vaccine has both anti-tumoral and anti-metastatic activity, and produces both antibodies that block VEGF-VEGF receptor interaction, and a specific T-cell cytotoxic response against tumor cells. CIGB-247, with an antigen dose of 100 μg, has been characterized by an excellent safety profile in mice, rats, rabbits, and non human primates. In this article we extend the immunogenicity and safety studies of CIGB-247 in non human primates, scaling the antigen dose from 100 μg to 200 and 400 μg/vaccination. Our results indicate that such dose escalation did not affect animal behavior, clinical status, and blood parameters and biochemistry. Also, vaccination did not interfere with skin deep skin wound healing. Anti-VEGF IgG antibodies and specific T-cell mediated responses were documented at all three studied doses. Antigen dose apparently did not determine differences in maximum antibody titer during the 8 weekly immunization induction phase, or the subsequent increase in antibodies seen for monthly boosters delivered afterwards. Higher antigen doses had a positive influence in antibody titer maintenance, after cessation of immunizations. Boosters were important to achieve maximum antibody VEGF blocking activity, and specific T-cell responses in all individuals. Purified IgG from CIGB-247 immunized monkey sera was able to impair proliferation and formation of capillary-like structures in Matrigel, for HMEC cells in culture. Altogether, these results support the further clinical development of the CIGB-247 therapeutic cancer vaccine, and inform on the potential mechanisms involved in its effect.

Peruvians’ sleep duration: analysis of a population-based survey on adolescents and adults

Background. Sleep duration, either short or long, has been associated with diseases such as obesity, type-2 diabetes and cardiovascular diseases. Characterizing the prevalence and patterns of sleep duration at the population-level, especially in resource-constrained settings, will provide informative evidence on a potentially modifiable risk factor. The aim of this study was to explore the patterns of sleep duration in the Peruvian adult and adolescent population, together with its socio-demographic profile. Material and Methods. A total of 12,424 subjects, mean age 35.8 years (SD ±17.7), 50.6% males, were included in the analysis. This is a cross-sectional study, secondary analysis of the Use of Time National Survey conducted in 2010. We used weighted means and proportions to describe sleep duration according to socio-demographic variables (area and region; sex; age; education attainment; asset index; martial and job status). We used Poisson regressions, taking into account the multistage sampling design of the survey, to calculate crude and adjusted prevalence ratios (PR) and 95% confidence intervals (95% CI). Main outcomes were short- (<6 h) and long-sleep duration (≥ 9 h). Results. On average, Peruvians slept 7.7 h (95% CI [7.4–8.0]) on weekdays and 8.0 h (95% CI [7.8–8.1]) during weekends. The proportions of short- and long-sleep, during weekdays, were 4.3% (95% CI [2.9%–6.3%]) and 22.4% (95% CI [14.9%–32.1%]), respectively. Regarding urban and rural areas, a much higher proportion of short-sleep was observed in the former (92.0% vs. 8.0%); both for weekdays and weekends. On the multivariable analysis, compared to regular-sleepers (≥ 6 to <9 h), short-sleepers were twice more likely to be older and to have higher educational status, and 50% more likely to be currently employed. Similarly, relative to regular-sleep, long-sleepers were more likely to have a lower socioeconomic status as per educational attainment. Conclusions. In this nationally representative sample, the sociodemographic profile of short-sleep contrasts the long-sleep. These scenarios in Peru, as depicted by sleeping duration, differ from patterns reported in other high-income settings and could serve as the basis to inform and to improve sleep habits in the population. Moreover, it seems important to address the higher frequency of short-sleep duration found in urban versus rural settings.

Cansancio y somnolencia durante el desempeño laboral de los conductores interprovinciales: experiencia peruana y planteamiento de propuestas

The information indicates that the traffic accidents caused by bus drivers’ sleepiness or tiredness are frequent in our country. A driver that falls asleep while driving cannot perform evasive maneuvers in order to avoid crashes or getting off the track, being the result of this kind of accidents a great number of victims and infrastructure destruction. In this article we discuss the original data published in Peru up to date and make general proposals to face the problem.

Cansancio y somnolencia en conductores de ómnibus interprovinciales: estudio comparativo entre formalidad e informalidad

Objectives. To compare the levels of fatigue, sleepiness and their consequences between formal and informal drivers of interprovincial buses. To evaluate labor conditions between both study groups. Materials and methods. A comparative cross-sectional study was performed with non-probabilistic sampling. 100 companies of land transport were included, out of which 17 were formal according to the official registries of the Ministry of Transport and Communications (MTC), the drivers were also classified as formal or informal. The survey included one questionnaire and a Peruvian validated version of the Epworth sleepiness scale. Results. 71 formal drivers and 274 informal drivers participated, all were males. Out of the 134 drivers that worked for the formal companies according to the MTC, only 43 (32%) belong to the formal group based on the proposed criteria. 48% (34) of the formal drivers and 43% (118) of the informal sleep less than 7 hours a day. 48% (34) of the formal and 49% (135) of the informal admitted having had an accident or “almost” having had it, the most frequent time of the day was between 01.00 and 04.00 in the morning. The dawn is the period in which both groups feel most tired. 44% (30) of the formal drivers and 54% (144) of the informal ones perform 5 or more night shifts per week. Out of the total of interviewed, 16% (56) had sleepiness. The association with road traffic accidents was similar. Conclusions. The fatigue and sleepiness levels were similar between formal and informal drivers. Companies classified as formal, have a high percentage of informality amongst their drivers.

Ratio of HCV structural antigens in protein-based vaccine formulations is critical for functional immune response induction

HCV (hepatitis C virus) infection is among the leading causes of chronic liver disease, but currently there is no vaccine available. Data have accumulated about the importance of targeting different HCV antigens in vaccine candidate preparations. Here, a surface response study to select the optimal ratio of recombinant HCV structural antigens in a vaccine preparation, capable of generating in vivo functional cellular immune response in mice, was performed. The immunogenicity of the selected HCV structural protein mixture (Co–E1–E2) in mice and African green monkeys, after five doses of immunization, was also demonstrated. Specific T‐cell proliferative response against HCV structural antigens was induced in vaccinated mice. Moreover, on challenge with recombinant HCV VV (vaccinia virus), all mice controlled the viraemia and 80% were protected. On the other hand, monkeys immunized with Co–E1–E2 developed antibodies, specifically directed to region 412–438 of E2 protein, that include an epitope implicated in HCV neutralization, in addition to a specific proliferative response against HCV Core and E2 proteins. These results indicated that the optimal amount and ratio of HCV recombinant proteins should be taken into account to elicit a successful immune response against HCV and therefore have important implications for vaccine design.

Olive baboons: a non-human primate model for testing dengue virus type 2 replication

OBJECTIVE This study evaluated the use of a non-human primate, the olive baboon (Papio anubis), as a model of dengue infection. Olive baboons closely resemble humans genetically and physiologically and have been used extensively for assessing novel vaccine formulations. METHODS Two doses of dengue virus type 2 (DENV-2) were tested in baboons: 10(3) and 10(4) pfu. Similarly, African green monkeys received the same quantity of virus and acted as positive controls. RESULTS Following exposure, high levels of viremia were detected in both animal species. There was a trend to detect more days of viremia and more homogeneous viral titers in animals receiving the low viral dose. In addition, baboons infected with the virus generally exhibited positive virus isolation 1 day later than African green monkeys. Humoral responses consisting of antiviral and neutralizing antibodies were detected in all animals after infection. CONCLUSIONS We conclude that baboons provide an alternative non-human primate species for experimental DENV-2 infection and we recommend their use for further tests of vaccines, administering the lowest dose assayed: 10(3) pfu.

Vaccination with a mutated variant of human Vascular Endothelial Growth Factor (VEGF) blocks VEGF-induced retinal neovascularization in a rabbit experimental model

Vascular Endothelial Growth Factor (VEGF) is a key driver of the neovascularization and vascular permeability that leads to the loss of visual acuity of eye diseases like wet age-related macular degeneration, diabetic macular edema, and retinopathy of premature. Among the several anti-VEGF therapies under investigation for the treatment of neovascular eye diseases, our group has developed the vaccine candidate CIGB-247-V that uses a mutated form of human VEGF as antigen. In this work we evaluated if the vaccine could prevent or attenuate VEGF-induced retinal neovascularization in the course of a rabbit eye neovascularization model, based on direct intravitreal injection of human VEGF. Our experimental findings have shown that anti-VEGF IgG antibodies induced by the vaccine were available in the retina blood circulation, and could neutralize in situ the neovascularization effect of VEGF. CIGB-247-V vaccination proved to effectively reduce retinal neovascularization caused by intravitreal VEGF injection. Altogether, these results open the way for human studies of the vaccine in neovascular eye syndromes, and inform on the potential mechanisms involved in its effect.

Diferencias clínicas y polisomnográficas entre obesos y no obesos con síndrome de apneas-hipopneas del sueño

Objetivos. Describir las diferencias clinicas y polisomnograficas en pacientes obesos y no obesos con diagnostico del sindrome de apneas-hipopneas del sueno (SAHS). Materiales y metodos. A los pacientes incluidos se les realizo un examen fisico, se aplico la escala de somnolencia de Epworth (ESE) y ademas se les realizo una polisomnografia. Se considero obeso si el indice de masa corporal (IMC) era mayor o igual a 30 kg/m2. Resultados. Se analizaron 408 pacientes con SAHS, de estos, 119 (47 %) fueron obesos. El SAHS fue leve en 101 (25 %), moderado en 91 (22 %) y severo en 216 (53 %). No hubo diferencias por sexo, edad y puntaje ESE al compararse obesos con no obesos. La diferencias del perimetro cervical y presencia de somnolencia segun ESE fue significativamente mayor en obesos. Estos tuvieron mayor comorbilidad en terminos de dislipidemia, hipertension arterial y enfermedad coronaria. De las variables polisomnograficas, los indices de eventos respiratorios fueron mayores en obesos, asimismo fueron peores los valores de saturacion de oxigeno. No hubo diferencias en el resto de variables. El analisis de regresion mostro asociacion entre la obesidad y la severidad del SAHS. Conclusiones. El SAHS no es una enfermedad limitada a la poblacion obesa, aunque esta ultima tienen mayor comorbilidad y formas mas severas de enfermedad.