Endoscopic papillectomy for ampullary lesions of minor papilla

BACKGROUND AND AIMS

Ampullary lesions (ALs) of the minor duodenal papilla are extremely rare. Endoscopic papillectomy (EP) is a routinely used treatment for AL of the major duodenal papilla, but the role of EP for minor AL has not been accurately studied.

METHODS

We identified 20 patients with ALs of minor duodenal papilla in the multicentric database from the Endoscopic Papillectomy vs Surgical Ampullectomy vs Pancreatitcoduodenectomy for Ampullary Neoplasm study, which included 1422 EPs. We used propensity score matching (nearest-neighbor method) to match these cases with ALs of the major duodenal papilla based on age, sex, histologic subtype, and size of the lesion in a 1:2 ratio. Cohorts were compared by means of chi-square or Fisher exact test as well as Mann-Whitney U test.

RESULTS

Propensity score-based matching identified a cohort of 60 (minor papilla 20, major papilla 40) patients with similar baseline characteristics. The most common histologic subtype of lesions of minor papilla was an ampullary adenoma in 12 patients (3 low-grade dysplasia and 9 high-grade dysplasia). Five patients revealed nonneoplastic lesions. Invasive cancer (T1a), adenomyoma, and neuroendocrine neoplasia were each found in 1 case. The rate of complete resection, en-bloc resection, and recurrences were similar between the groups. There were no severe adverse events after EP of lesions of minor papilla. One patient had delayed bleeding that could be treated by endoscopic hemostasis, and 2 patients showed a recurrence in surveillance endoscopy after a median follow-up of 21 months (interquartile range, 12-50 months).

CONCLUSIONS

EP is safe and effective in ALs of the minor duodenal papilla. Such lesions could be managed according to guidelines for EP of major duodenal papilla.

Feeding patterns of Triatoma vitticeps in the State of Rio de Janeiro, Brazil

OBJECTIVE

Feeding patterns of triatomines have contributed to elucidate its biology. Triatoma vitticeps, naturally infected with T. cruzi, has been found in domiciles. Its behavior and epidemiological patterns were investigated.

METHODS

One-hundred and twenty two specimens of T. vitticeps were captured from February 1989 to April 1993 in two areas of Triunfo municipality, a subdistrict of Santa Maria Madalena municipal district, State of Rio de Janeiro, Brazil. The insects were dissected and their intestinal contents were removed and tested. It was used antisera from: man, cow, horse, dog, pig, armadillo, opossum, rodent, and bird.

RESULTS

From the total analyzed, 79 were positive and 43 were negative to the nine antisera tested: armadillo (30.3%) > human and pig (13.1%) > bird and dog (11.5%) > horse (5.7%) > opossum (4.9%) > rodent (4. 1%) > cow (3.3%). Blood meals ranged from 0 to 4 and 6 in the following distribution: 0 = 25.41%; 1 = 45.08%; 2 = 10.66%; 3 = 6. 56%; 4 = 1.64%, and 6 = 0.82%. Nine of the 122 insects captured were not examined, 74 (65.54%) were positive for T. cruzi infection and 39 (34.51%) were negative.

CONCLUSIONS

These results identified the T. vitticeps as being a sylvatic species and trypanosomiasis as being an enzootic disease. Epidemiological vigilance will be important to provide more information regarding the behavior of the species

An investigation on the ecology of Triatoma vitticeps (Stal, 1859) and its possible role in the transmission of Trypanosoma cruzi, in the locality of Triunfo, Santa Maria Madalena municipal district, state of Rio de Janeiro, Brazil

From January 1989 to April 1995, 465 specimens of Triatoma vitticeps were collected in the locality of Triunfo, 2nd District of Santa Maria Madalena municipal district, State of Rio de Janeiro. The bugs were found indoors by local residents with predominance of adults. The flight activity was high in hot months when the incidence in the domicile also increased. Two hundred and two bugs (111 alive and 91 dead) were examined for Trypanosoma cruzi infection. This was detected in 31 of the dead bugs (34%) and 88 (79%) of the live bugs examined. With a view to investigate the possible vertebrate hosts of the T. cruzi isolates, the blood of 122 mammals was examined through Giemsa-stained smears, hemocultures and xenodiagnosis. T. cruzi was detected in three specimens of Didelphis marsupialis and T. (M.) theileri was detected in one specimen of Bos taurus. The parasites were isolated from triatomine feces, xenoculture and hemoculture. No evidence of human infection was detected in 58 inhabitants examined, as evaluated by indirect imunofluorescence technique using T. cruzi epimastigotes as antigens. These results show that T. vitticeps is still a sylvatic species although nymphs have been found inside the domicile. Thus, an epidemiological vigilance is necessary to know the behaviour of this species following the continuous modifications promoted by the presence of man.

Resistance to starvation of Triatoma rubrofasciata (De Geer, 1773) under laboratory conditions (Hemiptera: Reduviidae: Triatominae)

The present work aims at learning the period of resistance to starvation (molting/death) of Triatoma rubrofasciata in different stages of development and the respective loss of weight until death. Eggs of specimens from the greater area of the city of São Luis in the State of Maranhão, Brazil, yielded approximately 300 nymphs. These nymphs were placed in labelled Borrel glasses, in which they were weekly fed on rats (Rattus norvegicus), until reaching the stage to be observed. The experiments were conducted in a climatic chamber regulated at 29 +/- 1 degrees C, 70% relative humidity and 12 hr photoperiod. The resistance to starvation increased according to the stage of development, except for adult bugs, whose results were similar to the 3rd stage nymphs. In all these development stages there was an abrupt loss of weight in the first week, followed by a gradual loss until death. Comparing this work with those of other authors, it was observed that T. rubrofasciata is among the less resistant triatomine species.

The effect of azadirachtin on fresh isolates of Trypanosoma cruzi in different species of triatomines

The effect of azadirachtin was investigated using three different fresh isolates of Trypanosoma cruzi and five different triatomine species which were infected as third-instar larvae. The two T. cruzi strains which originated from sylvatic Triatoma vitticeps showed a high prevalence after the molt to the fifth instar in Panstrongylus megistus and Rhodnius neglectus and a low prevalence in Triatoma infestans and Rhodnius robustus. The third T. cruzi strain originating from a patient in Piaui showed a high prevalence in P. megistus, R. neglectus and T. infestans and a low prevalence in Triatoma sordida. Feeding the infected fifth instars with azadirachtin-supplemented blood (1 microg/ml) resulted 20 days later in some parasite/vector combinations in an increase, in others a decrease or an unchanged number of T. cruzi in comparison to bugs fed with unsupplemented blood.

[Various aspects of the biology of Triatoma pseudomaculata Corrêa & Espínola, 1964, in laboratory conditions (Hemiptera:Reduviidae:Triatominae)]

Observations were made on the evolutive cycle of Triatoma pseudomaculata, held under laboratory conditions, fed weekly on bird (pigeon). Of 60 eggs obtained, only 34 nymphs reached the adult stage in a period of X(S) = 398 +/- 76 days. The following parameters were observed: the time immature stages took to develop from egg to adult emergence; the occurrence of the first meal; the time-lapse between the presenting of the blood-meal and the beginning of feeding; time of feeding; amount of blood ingested; variation of weight 24 hr after the blood-meal and until the next blood-meal; and the defecation pattern. The experiment was carried out for 20 months, held in BOD incubator with the average of temperature and humidity of 28 +/- 1 degrees C and 80 +/- 5% RU, respectively.

[Biology of Triatoma vitticeps (Stal, 1859) under laboratory conditions (Hemiptera: Reduviidae: Triatominae). II. Resistance to fasting]

Following the study on the biology of Triatoma vitticeps (Gonçalves et al., 1988) observations have been made on its resistance to starvation. Of the 286 eggs obtained only 201 hatched and reached the intended stage for observation. The others did not eclode, neither reached the ecdisis nor died, without explanation. The nymphs were kept, separately, in Borrel flasks and properly listed. The blood-meal was performed in mice, although the insects were kept without feeding as soon as moulted. The starvation was evaluated in two ways: the time-lapse in days between the last meal/death and between moult/death. The starvation was directly related with the developmental stage. In relation to the parameters last meal/death and moult/death, both sexes were less resistant than 3rd and 2nd stage, respectively. The experiment have been carried out for 15 months and by this time the average minimum and maximum temperatures and the humidity were 25 +/- 2 degrees C - 28 +/- 2 degrees C and 81 +/- 3% UR, respectively. The material spent belongs to the triatomine colony of the Oswaldo Cruz Institute Department of Entomology.

[Biology of Triatoma vitticeps (Stal, 1859) under laboratory conditions (Hemiptera: Reduviidae: Triatominae). I. Evolutive cycle]

Observations were made on the evolutive cycle of Triatoma vitticeps, held under laboratory conditions and fed weekly in mice. Of the 435 eggs obtained, from 4 virgin couples, 149 were purposed for the biological cycle study and 286 to evaluate their resistance to starvation, which shall be a second part of this work. Only 50 specimens reached the adult stage in a period of means (S) = 270 +/- 45 days. At the incubation time, the first and second instars were of less than a month for each, while the third, fourth and fifth instars requires approximately one, two and three months, respectively. The search for the first meal occurred clearly on the 3rd, 6th and 10th day. During all the stages, more than 50% of the specimens had only one blood-meal, except the fifth one, when two blood-meals were required. In relation to the time-lapse between the presenting of the blood-meal and the beginning of feeding, as well as the length of the blood-meal, it was observed that these increased gradually according to the stage. From the 423 blood-meals performed, 390 were not followed by defecation in the settled period of 10 min. Under this point of view, T. vitticeps seems to be a poor transmissor of T. cruzi. The experiment was carried out for 13 months and by this time the averages of minimum and maximum temperatures and the humidity were 25 +/- 2 degrees C - 28 +/- 2 degrees C and 80 +/- 2%, respectively. The material belongs to the triatomine colony held at the Oswaldo Cruz Institute, Department of Entomology.

[Biomorphogenetic changes caused by the application of precocene II in nymphs of Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae, Triatominae)]

The morphogenetic effect of precocene II on 4th instar nymphs of Triatoma infestans was examined. Topical treatment with precocene II (200, 300 and 400 micrograms/nymph) induced the formation of adultoids with the following characteristics: rudimentary wings, three segmented tarsi, ocelli, deformed genitalia and mouth-parts and testes with intermediary development. Precocene II also increases the duration of the molting cycle. The survival of the adultoid insects was related to the inverse of the applied doses. These data extend our knowledge of the action of precocene II on triatominae species.

[Morphogenetic effects of precocene II on nymphs of Rhodnius prolixus (Stal, 1859) (Hemiptera-Triatominae)]

The morphogenetic effects of Precocene II in nymphs of 1st-, 2nd-, 3rd-, and 4th-instar of Rhodnius prolixus were studied. A high number of insects underwent precocious metamorphosis by topical treatment (10-30 micrograms/insect) or adding the drug to the blood meal (25 micrograms/ml of blood). Adultoids of 4th- and 5th-instar, obtained by both treatments of 3rd- and 4th-instar, respectively, had mainly fully adult abdominal cuticle, ocelli, three segmented tarsi, rudimentary wings containing adult articulation with the thorax and deformed genitalia while adultiforms of 2nd- and 3rd-instar had very slight imaginal morphological characteristics. Topical treatment induced a high mortality in nymphs of 1st-instar and Precocene II given orally produced a high number of adultoids in this instar. The mode of application and the action of Precocene II on different nymphal instars were interpreted.