Colonization of rock pile boundary walls in fields by sylvatic triatomines (Hemiptera: Reduviidae) in Jalisco State, Mexico

Granite rocks is a very abundant material in Mexico because they are used habitually as borders for fields. The current work established the significance of this ecotype as a colonization site for triatomines of the Phyllosoma complex. Seven sites, arbitrary selected, in San Martin de Hidalgo municipality (Mexico) were investigated in April 2002 by using 210 mouse bait-traps left during the night in wall hollows. One hundred and seventy-two triatomines of all life stages were collected from the seven sites. Triatomines adhered to the tape that covered the traps or were found near them, and 36.6% of the traps collected triatomines. The principal species was Triatomia longipennis Usinger (1939) and low numbers of Triatoma picturata Usinger (1939) were found. The nymphal population was very young, probably corresponding to the reproductive period in April (end of the dry season). The infection rate of the triatomines for Trypanosoma cruzi was 49%. Because collecting triatomines in the field is laborious and time-consuming, the mouse bait-trap method found to be practical to assess the population of triatomines within a sylvatic habitat.     

Spatial structuring of Triatoma infestans (Hemiptera, Reduviidae) populations from northwestern Argentina using wing geometric morphometry

Wing geometric morphometry was used to study the spatial structuring of populations of Triatoma infestans from different villages, ecotopes, and sites within a village in northwestern Argentina. A total of 308 male and 197 female wings of T. infestans collected from peridomestic and domestic ecotopes in March 2000 was analyzed. On average, female bugs had a significantly larger wing size than males. Triatomines collected from domiciles or structures associated with chickens had larger wings than bugs collected from goat or pig corrals. The wing size of bugs did not differ significantly between villages. Discriminant analyses of wing shape showed significant divergence between villages, ecotopes, and individual collection sites. The study of metric variation of males between sites belonging to the same ecotope also revealed significant heterogeneity. Indeed, within the same section of the village the difference between two goat corrals was sometimes greater than that between neighboring goat and pig corrals. Thus, morphometric heterogeneity within villages may be the result not only of ecotope and host associations, but also of physical isolation between subunits. The strong structuring of T. infestans populations in the study area indicates that recolonization could be traced back to a small geographic source.     

An alternative immunohistochemical method for detecting Leishmania amastigotes in paraffin-embedded canine tissues

Canine visceral leishmaniasis (CVL) is a zoonosis and a chronic systemic disease of the dog caused by a protozoan by the species Leishmania infantum in the Old World and Leishmania chagasi in the New World. Several methods are currently employed for the diagnosis of CVL including microscopic detection of the parasite in bone marrow and lymph node aspirates, demonstration of specific antibodies anti-Leishmania in sera from infected animals, and isolation of the parasite by in vitro culture or by inoculation of laboratory animals. However, a definitive diagnosis is based on the actual detection of the parasite, which is conventionally achieved by examining Giemsa-stained smears or histopathological sections stained with hematoxylin and eosin. These methods have a low sensitivity, and therefore, they are often inconclusive. This is particularly true in canine organs that have a low level of parasitism such as kidneys, lungs, central nervous system, and testis, or, in some cases, the skin. The technique for immunohistochemical detection of leishmanial amastigotes in canine tissues has been reported previously and has proved to be undoubtedly efficient for the diagnosis. In this paper, we describe a straightforward and inexpensive immunohistochemical approach for Leishmania detection in formalin-fixed paraffin-embedded canine tissues. Amastigote forms of Leishmania were easily observed within macrophages in several organs from naturally infected dogs using the streptavidin-biotin immunohistochemical method with canine hyperimmune serum as the primary antibody. In addition, the secondary antibody used was not specific to canine immunoglobulin, characterizing a cross-immune reaction. Our results indicate that this technique could be a useful tool for epidemiological, clinical, and histopathological studies.     

Immunolocalization of HLA-DR and metallothionein on amalgam tattoos

Despite studies concerning toxic reactions related to amalgam components in the literature, few studies have been devoted to evaluate local noxious effects of amalgam tattoos (AT) on biological tissues. In addition, little is known about activation of inflammatory cells by mucosa-implanted amalgam debris. Tissue reaction to AT depends on the particle size. Human leukocyte antigen DR (HLA-DR) is an activation marker of inflammatory cells associated with antigen presentation. Metallothioneins (MT) are proteins involved with metal detoxication, including mercury and silver. The purpose of the present study was to investigate the immunolocalization of HLA-DR and MT in AT with large or powdered particles. Paraffin-embedded AT tissue blocks were sectioned and subjected to immunohistochemistry for HLA-DR and MT localization. The results demonstrated a dense mononuclear inflammatory infiltrate associated with large and powdered debris and positivity for HLA-DR and MT in inflammatory cells. While blood vessel walls and connective fibers impregnated with powdered particles were negative for HLA-DR, they were positive for MT. In addition, wherever epithelial basement membrane impregnation by powdered amalgam particles was observed, a strong positivity for MT was detected. These findings demonstrate that residual elements of AT still have noxious local effects over tissues.     

Single-step, self-etch adhesives behave as permeable membranes after polymerization. Part I. Bond strength and morphologic evidence

PURPOSE: To test the hypotheses that microtensile bond strengths of single-step, self-etch adhesives to hydrated dentin are adversely affected by delayed-activation of a light-cured composite, as well as the use of a chemical-cured composite. METHODS: Seven commercially available and one experimental single-step, self-etch adhesives were bonded to hydrated human dentin. A dual-cured composite was used and activated using: [1] the light-cured mode (base paste only-control), [2] the chemical-cured mode (base and catalyst pastes, in the dark); and [3] delayed light-activation (base syringe only, left on top of cured adhesives in the dark for 20 minutes before activation). After microtensile bond strength evaluation, fractured samples were examined using SEM. Intact, unstressed interfaces of [1] and [3] were examined with TEM. Microtensile bond strengths were also evaluated for selected adhesives bonded to dehydrated dentin and coupled with the composite activated by [2] or [3]. RESULTS: For all adhesives, bond strengths decreased significantly to bonded hydrated dentin when the composites were activated with [2] or [3] (P< 0.001). Whereas the hybrid layer-adhesive interface was intact, water-blisters that developed along the adhesive-composite interface in these two modes were responsible for the decline in bond strength. When bonded to dehydrated dentin, delayed light-activation of the light-cured composite did not result in compromised bond strength. The results of chemical-cured composites improved but were more variable and system-dependent.     

Congenital duodenal obstruction: does prenatal diagnosis improve the outcome?

Prenatal diagnosis of congenital duodenal obstruction (CDO) provides information about associated anomalies; helps plan the delivery, resuscitation, and neonatal surgery; and allows for appropriate family counseling. This report compares the outcomes of two groups of newborns: one with prenatal diagnosis of CDO (group I) and the other without (group II). Charts of the 23 newborns with CDO admitted to the Hospital of UNICAMP between 1993 and 2001 were retrospectively reviewed. Ten (44%) newborns had prenatal diagnosis of CDO. Among group I patients, the postnatal diagnosis was confirmed on the 1st day of life, whereas patients without prenatal diagnosis (group II) had the diagnosis of CDO confirmed at a mean age of 5.7 days (p=0.004). The mean ages at surgery, at total oral feeding, and at hospital discharge were also statistically lower among infants with prenatal diagnosis, and more complications occurred in group II patients. The earlier care could explain the statistically lower morbidity for patients with prenatal diagnosis, since they were able to undergo further investigation and surgical repair before any impairment to their clinical status could take place. We believe that prenatal diagnosis of CDO, associated with earlier surgery and adequate postoperative support, can provide lower morbidity, decrease the hospitalization period, and, therefore, decrease its costs to the state and to society.     

Fungal biofilm formation on cochlear implant hardware after antibiotic-induced fungal overgrowth within the middle ear

Cochlear implantation in patients with chronic suppurative otitis media is managed with perioperative antibiotics; however, fungal overgrowth can occur. We present a child who received oral cefdinir and topical ofloxacin (Floxin). After 6 weeks, a fungal (Candida) biofilm was demonstrated on the implant surface. In this clinical setting, an antimicrobial strategy using an oral antifungal to prevent fungal overgrowth is a possibility.