Viability of Campylobacter spp. in frozen and chilled broiler carcasses according to real-time PCR with propidium monoazide pretreatment.

The aim of this study was to evaluate the viability of Campylobacter spp. in frozen and chilled broiler carcasses using real-time PCR with propidium monoazide (PMA) pretreatment. Sixty broiler carcasses were collected: 30 frozen and 30 chilled. Each carcass was submitted to 2 real-time PCR protocols to detect and quantify Campylobacter spp.: one using pretreatment with PMA, which blocks the amplification of DNA from dead bacteria, and the other without PMA. The results showed that PMA-pretreated carcasses, either frozen or chilled, had a lower positivity rate compared to untreated samples (P < 0.001). Regarding storage temperatures, PMA-pretreated frozen carcasses that tested positive were in a lesser number than chilled carcasses (P < 0.05). However, the quantification of total and live bacteria in PMA-pretreated frozen carcasses that tested positive showed no significant difference compared to chilled carcasses. It was concluded that the real-time PCR with PMA pretreatment was a sensitive method for evaluating the viability of Campylobacter spp. in broiler carcasses. Chilled broiler carcasses would represent greater hazard to public health concerning Campylobacter transmission.

Morphology of mitochondrial permeability transition: morphometric volumetry in apoptotic cells.

Here we report on the mitochondrial permeability transition (MPT), which refers to the morphology of mitochondria whose inner membrane has lost its selective permeability. In all types of apoptotic cells so far examined, we found outer mitochondrial membranes that had been ruptured. These mitochondria present a swollen matrix covered by an inner membrane herniating into the cytoplasm through the breached outer membrane. Similarly ruptured outer mitochondrial membranes have been reported in studies on mitochondrial fractions induced to undergo MPT, carried out by others. Our observations were made on five types of rat tissue cells and six different cultured cell lines in the early stages of apoptosis. Samples from the cell lines HL-60, HeLa, WEHI-164, and a special batch of PC-12 cells were subjected to various apoptogenic agents and analyzed morphometrically. Nonapoptotic companion cells with unaltered nuclear structure (CUNS) were also analyzed. The mitochondrial volume in microm(3) and the volume fraction of the cytoplasm occupied by mitochondria in cells with typical nuclear signs of apoptosis and also in CUNS were evaluated. The volume of the mitochondria with ruptured membrane represents at least 69% (47-89%) of the total mitochondrial volume of the apoptotic cells. Thus, a considerable fraction of the cellular mitochondrial mass is or was in the state of permeability transition and probably involved in enhancement of the apoptotic program. In all samples, a fraction of the cells with normal nuclei possessed mitochondria with breached outer membranes as described above. In these cells, MPT occurred before the appearance of the typical nuclear phenotype of the apoptotic cells.

Trends in the prevalence of Chagas' disease among first-time blood donors in São Paulo, Brazil.

BACKGROUND: Screening of blood donors for Chagas' disease is mandatory in Brazil. Data about the prevalence of Chagas' disease among first-time blood donors has not been previously reported. The objective of this study was to report the trends in the prevalence of Chagas' disease among first-time blood donors in São Paulo, Brazil according to gender, age, and type of donation. STUDY DESIGN AND METHODS: The data was obtained at Fundação Pró-Sangue/Hemocentro de São Paulo during the period of 1996 to 2001. Samples were considered positive if they were reactive to the three serologic tests used at screening (indirect immunofluorescence, indirect hemagglutination, and EIA). RESULTS: The prevalence of Chagas' disease was two times higher among replacement blood donors than among altruistic donors (52 vs. 25 cases/10,000). The overall prevalence among blood donors decreased at a rate of 1.86 cases per 10,000 per year. An increase in the proportion of altruistic donors and a decrease in the prevalence primarily among younger donors were observed. CONCLUSION: The prevalence of Chagas' disease is decreasing in the São Paulo population. Differences in the socioeconomic level between altruistic and replacement donors may be the reason for the differences in the prevalence among these groups. It will be important to target for study the population of young seroreactive blood donors to better understand how new infections are occurring.