Development of Films, Based on Oxidized Ipomea Batatas Starch, with Protein Encapsulation / Desarrollo de Películas, Basadas en Almidón Oxidado de Ipomea Batatas, con Encapsulación de Proteínas

ABSTRACT Dialdehyde starches (DAS) have been used as biomaterials due to their biocompatibility and biodegradability; nonetheless, sweet potato (Ipomea batatas L.) starch has not been researched. Films based on sweet potato DAS, mixed with native starch (NS), poly-vinyl alcohol (PVA) and glycerin have been developed with protein encapsulation, using central composite design (CCD) and response surface methodology (RSM). Input variables were oxidation degree, NS concentration and polymeric mixture volume, while output variables were film's thickness, equilibrium swelling and BSA (Bovine serum albumin) release. DAS was obtained through hydrogen peroxide (H2O2) oxidation, and the oxidation degree is referred to as H2O2 concentration. Films presented rough surfaces, and formulations containing 10% H2O2 DAS presented micropores. Water uptake was greater with higher DAS content. Film thickness depended on the volume of the polymeric suspension and influenced swelling capacity. According to RSM, the optimal formulation was DAS with 5% H2O2 and 35% NS. These results demonstrate that oxidized sweet potato starch has potential for protein encapsulation and delivery.

RESUMEN Almidones dialdehído (DAS) se han utilizado como biomateriales por su biocompatibilidad y biodegradabilidad; sin embargo, el almidón de camote (Ipomea batatas L.) no ha sido investigado. Se han desarrollado películas de DAS de camote, con almidón nativo (NS), alcohol polivinílico (PVA) y glicerina con encapsulación de proteínas, utilizando un diseño central compuesto (CCD) y metodología de superficie de respuesta (RSM). Las variables de entrada fueron: grado de oxidación, concentración de NS y volumen de la mezcla polimérica, mientras que las variables de salida fueron: espesor de la película, hinchamiento y liberación de BSA (Albúmina de Suero Bovino) en equilibrio. DAS se obtuvo mediante oxidación con peróxido de hidrógeno (H2O2), y el grado de oxidación se define como concentración de H2O2. Las películas presentaron superficies rugosas y las formulaciones con 10% H2O2 DAS presentaron microporos. La absorción de agua fue mayor con mayor contenido de DAS. El espesor de la película dependió del volumen de la mezcla polimérica e influyó en la capacidad de hinchamiento. Según RSM, la formulación óptima fue DAS con 5% H2O2 y 35% NS. Estos resultados demuestran que el almidón de camote oxidado tiene potencial para aplicaciones en la encapsulación y liberación de proteínas.

An outbreak of plague including cases with probable pneumonic infection, Ecuador, 1998.

During February and March of 1998, 12 sudden deaths were reported among residents of a high-Andean community in Ecuador. All 12 fatalities were members of the same extended family and some had apparent exposure to sick guinea-pigs. Following an initial investigation by public health officials, an additional death was reported in a nearby community in April, also associated with exposure to sick guinea-pigs. Blood samples from humans, dogs, and a rodent were tested for antibody to the F1 antigen of Yersinia pestis by passive haemagglutination assay. Tissue from rodents was subjected to direct fluorescent antibody staining using fluorescein-labelled monoclonal antibody to Y. pestis F1 antigen. Formalin-fixed specimens from the 2 autopsies were evaluated using a 2-step alkaline phosphatase immunoassay with a monoclonal antibody to Y. pestis F1 antigen, and tissues that had not been embedded in paraffin were tested for the presence of DNA encoding the F1 structural antigen by polymerase chain reaction. Serological evaluation of close contacts of the fatalities revealed positive titres to F1 antigen of Y. pestis, the aetiological agent of plague, in 3 contacts from the first community and 1 from the second. Immunohistochemical staining of tissues collected from 2 of the fatalities provided evidence that both had pneumonic plague. Five of 14 dogs found in the communities were seropositive for plague antibody, providing evidence of a recent epizootic plague in the area.

The effect of antimalarial chloroquine therapy and prophylaxis on concurrent infection with Onchocerca volvulus in Ecuador.

The effect of chloroquine phosphate on Onchocerca volvulus in vivo was studied in Ecuadorians undergoing treatment for malaria. All persons with a diagnosis of acute malaria and treated with 2500 mg of chloroquine over 3 d showed a 100% reduction of dermal O. volvulus microfilariae 7 d after treatment. However, 28 d after treatment the microfilarial densities returned to their pre-treatment levels and at 35 d they had increased to 121.6% of their pre-treatment values. Treatment did not appear to have any effect on the adult O. volvulus examined histologically in extirpated nodules. Patients treated for acute malaria and subsequently kept on a prophylactic regimen of 500 mg chloroquine weekly showed a reduction of 56.7% from pre-treatment microfilarial density after 27 weeks. Patients who underwent nodulectomy as well as treatment for acute malaria and were given 500 mg of chloroquine prophylactically for 27 weeks showed a reduction in dermal microfilarial density of 93.6%. Symptoms of onchocerciasis were reduced in the latter group of patients, with the elimination of all acute dermatological changes within 6 weeks. Ocular examination of these surgically and chemotherapeutically treated individuals revealed reductions of 94.9% of microfilariae in the anterior chamber, 95.9% of live microfilariae in the cornea, and 95.1% of dead microfilariae in the cornea. There was a reduction of 69.8% in corneal fluffy opacities. No alteration in the visual acuity or in visible lesions in the posterior segment was recorded. The results suggest that a complex interaction between chloroquine and O. volvulus takes place in vivo, which can be beneficial to the patient over a long period.(ABSTRACT TRUNCATED AT 250 WORDS)

Estudios operativos sobre el control de la teniasis/cisticercosis por taenia solium en el Ecuador / Operational studies on the control of taenia solium taeniasis/cysticercosis in Ecuador

Operational studies on the control of taenia solium taeniasis/cysticercosis in Ecuador

Se pública en inglés en el Bull. WHO 67((4), 1989

Onchocerciasis in Ecuador, 1980-1986: epidemiological evaluation of the disease in the Esmeraldas province.

An increase in both the prevalence (68.3%) and intensity of infection (106.2%) occurred in the Ecuadorian onchocercal focus during the 6 year period, 1980 to 1986. In 1986, a higher prevalence of infection was noted in males (53.6%) than females (33.1%), but a greater rate of increase of infection over the 6 years was seen in females than males (75.7% vs 61.9% respectively). In all endemic areas, the Chachi race had a higher prevalence of infection as well as higher increase rate of infection than the Black. In the hyperendemic and hypoendemic areas the highest increase of infection was seen in the Chachi female and Chachi male respectively. The prevalence of infection in 1986 was greater than that in 1980 for all ages, with the greatest increase of infection in the 1-4 year age groups. There was an average increase of 106.2% in the microfilarial skin density with an increase seen in all age groups. A higher microfilariae density increase was seen in the hypoendemic (100.0%) than the hyperendemic (66.5%) areas. The Blacks showed a greater microfilarial density increase than the Chachi (155.1% vs 70.7% respectively) with the Black female showing the highest increase (117.6%) in the hyperendemic area and the Black male showing the highest (155.6%) in the hypoendemic area. Along the Rio Cayapas, high microfilarial densities were found in 3 major areas on the river, a reflection of man-vector exposure.

Onchodermatitis--correlation between skin disease and parasitic load in an endemic focus in Ecuador.

Onchocerciasis is a chronic parasitic infection in which infiltration of the skin by microfilariae has been associated with a number of different pathological changes. This survey compared the prevalence of different forms of skin disease in two villages, one of which was located within the endemic zone for onchocerciasis (Zapallo Grande), in a lowland rain forest area of western Ecuador. The commonest skin diseases in both villages were scabies, pyoderma and pityriasis versicolor. In addition changes closely correlated with the presence of microfilariae in skin snips were found in Zapallo Grande--such as atrophic gluteal changes, and acute and chronic papular dermatitis. The only other skin disease associated with onchocerciasis was widespread tinea corporis due to T. rubrum. The Amerindians in the endemic onchocerciasis area were more likely than Negroes to have generalized atrophic changes of the skin, whereas in the latter group significant numbers of individuals had no obvious skin lesions but large numbers of microfilariae were detected in skin snips. Acute papular dermatitis was common in both groups and in biopsied lesions microfilariae could usually be identified within the epidermis or close to the dermo-epidermal junction. One patient had developed severe reactive onchodermatitis (Sowda). Swabs taken from onchocercal skin lesions showed no evidence of skin surface carriage of Staphylococcus aureus. Changes classically associated with onchocerciasis such as pretibial hypopigmentation (leopard skin) and hanging groin were notably absent in this population.

Operational studies on the control of Taenia solium taeniasis/cysticercosis in Ecuador.

A large-scale study in Loja and El Oro Provinces, Ecuador, demonstrated that population-based treatment of human taeniasis with a low dose of praziquantel is feasible and effective for the short-term control of transmission of Taenia solium in hyperendemic areas. Chemotherapeutic intervention also effectively promoted local preventive measures and contributed greatly to the elaboration of a long-term control programme.

Onchocerciasis in Ecuador: absence of microfilaraemia.

Blood samples from 497 people positive for onchocerciasis in the hyperendemic onchocercal focus in Ecuador were analysed for the presence of microfilaraemia using the Knott technique. No evidence of Onchocerca volvulus microfilaraemia was found, nor that of any other microfilaria.

Pilot study to detect neurologic disease in Ecuador among a population with a high prevalence of endemic goiter.

A census, uniform screening questionnaire, and simple screening neurologic examination were administered in a door-to-door survey to residents of Quiroga, Ecuador, a rural community in the Andes Mountains. The screening procedures had been pretested to assure a high level of sensitivity for detecting children and adults with major neurologic disease. A total of 1,113 participated in the study. Of these, 399 had responses or findings suggesting the presence of neurologic disease. These individuals were then examined by a neurologist, who used fixed diagnostic criteria. The prevalence ratios (per 1,000) for the most common neurologic conditions identified in this survey are: recurrent/persistent severe headache = 68.3, and epilepsy = 17.1.