Study of appendicitis in children treated with four different antibiotic regimens

This is a prospective and randomized study of 100 patients with acute appendicitis who were less than 10 years old, in which four different antibiotic regimens commonly in use against gram-negative and anaerobic bacteria were compared in terms of postoperative septic complications. The antibiotics were begun immediately preoperatively and continued for five days. Ten percent of the patients developed infection complications, with 4% requiring further surgery. The best results were obtained with cefoxitin (4% of infection), metronidazole plus amikacin and latamoxef (8%), while the regimen of clindamycin plus amikacin was associated with the greatest number of complications (20%). On analyzing the main microbiologic findings of the study, we conclude that some sort of antibiotic treatment is indicated in all types of appendicitis, due to the occult presence of bacteria in the peritoneal cavity, even without clinical evidence of gangrene or perforation. Further, we emphasize the significance of Streptococcus faecalis as being responsible, along with Escherichia coli and Bacteroides fragilis, for serious postoperative complications.     

Meningitis due to mixed infection with penicillin-resistant and penicillin-susceptible strains of Streptococcus pneumoniae

Streptococcus pneumoniae is the major cause of bacterial meningitis. We report a case of meningitis due to a mixed infection with two distinct strains of S. pneumoniae: one penicillin-resistant strain of serotype 9V and one penicillin-susceptible strain of serotype 7. The two strains exhibited different pulsed-field gel electrophoresis profiles.     

Synthesis and leishmanicidal activity of cinnamic acid esters: structure–activity relationship

Several cinnamic acid esters were obtained via Fischer esterification of cinnamic acids derivatives with aliphatic alcohols. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes and cytotoxic activity was evaluated against mammalian U-937 cells. The compounds 11, 15–17, and 23, were active against Leishmania parasite and although toxic for mammalian cells, they still are potential candidates for antileishmanial drug development. A SAR analysis indicates that first, while smaller alkyl chains lead to higher selectivity indices (10, 11 vs. 12–17); second, the degree of oxygenation is essential for activity, primarily in positions 3 and 4 (17 vs. 18–20 and 22); and third, hydroxyl groups increase both activity and cytotoxicity (14 vs. 23). On the other hand, the presence of a double bond in the side chain is crucial for cytotoxicity and leishmanicidal activity (12 vs. 21). However, further studies are required to optimize the structure of the promising molecules and to validate the in vitro activity against Leishmania demonstrated here with in vivo studies.     

Detection of Anatoxin-a and Three Analogs in Anabaena spp. Cultures: New Fluorescence Polarization Assay and Toxin Profile by LC-MS/MS

Anatoxin-a (ATX) is a potent neurotoxin produced by several species of Anabaena spp. Cyanobacteria blooms around the world have been increasing in recent years; therefore, it is urgent to develop sensitive techniques that unequivocally confirm the presence of these toxins in fresh water and cyanobacterial samples. In addition, the identification of different ATX analogues is essential to later determine its toxicity. In this paper we designed a fluorescent polarization (FP) method to detect ATXs in water samples. A nicotinic acetylcholine receptor (nAChR) labeled with a fluorescein derivative was used to develop this assay. Data showed a direct relationship between the amount of toxin in a sample and the changes in the polarization degree of the emitted light by the labeled nAChR, indicating an interaction between the two molecules. This method was used to measure the amount of ATX in three Anabaena spp. cultures. Results indicate that it is a good method to show ATXs presence in algal samples. In order to check the toxin profile of Anabaena cultures a LC-MS/MS method was also developed. Within this new method, ATX-a, retention time (RT) 5 min, and three other molecules with a mass m/z 180.1 eluting at 4.14 min, 5.90 min and 7.14 min with MS/MS spectra characteristic of ATX toxin group not previously identified were detected in the Anabaena spp. cultures. These ATX analogues may have an important role in the toxicity of the sample.     

Influence of Two Depuration Periods on the Activity and Transcription of Antioxidant Enzymes in Tilapia Exposed to Repeated Doses of Cylindrospermopsin under Laboratory Conditions

The cyanobacterial toxin Cylindrospermopsin (CYN), a potent protein synthesis inhibitor, is increasingly being found in freshwater bodies infested by cyanobacterial blooms worldwide. Moreover, it has been reported to be implicated in human intoxications and animal mortality. Recently, the alteration of the activity and gene expression of some glutathione related enzymes in tilapias (Oreochromis niloticus) exposed to a single dose of CYN has been reported. However, little is known about the effects induced by repeated doses of this toxin in tilapias exposed by immersion and the potential reversion of these biochemical alterations after two different depuration periods (3 or 7 days). In the present study, tilapias were exposed by immersion to repeated doses of a CYN-containing culture of Aphanizomenon ovalisporum during 14 days, and then were subjected to depuration periods (3 or 7 days) in clean water in order to examine the potential reversion of the effects observed. The activity and relative mRNA expression by real-time polymerase chain reaction (PCR) of the antioxidant enzymes glutathione peroxidase (GPx) and soluble glutathione-S-transferases (sGST), and also the sGST protein abundance by Western blot analysis were evaluated in liver and kidney of fish. Results showed significant alterations in most of the parameters evaluated and their recovery after 3 days (GPx activity, sGST relative abundance) or 7 days (GPx gene expression, sGST activity). These findings not only confirm the oxidative stress effects produced in fish by cyanobacterial cells containing CYN, but also show the effectiveness of depuration processes in mitigating the CYN-containing culture toxic effects.     

HIV prevalence and correlates of receptive needle sharing among injection drug users in the Mexican-U.s. border city of Tijuana

Injection drug use is a growing but understudied problem in Tijuana, a city situated on the northwestern Mexico-U.S border. The authors studied factors associated with receptive needle sharing in an effort to inform prevention activities. In 2003, street-recruited injection drug users (IDUs) in Tijuana underwent interviews on injection risk behaviors and rapid HIV antibody tests. Logistic regression was used to identify correlates of receptive needle sharing at the last injection episode. Of 402 IDUs, 87.6% were male; the median age was 34. HIV prevalence was 4.01% (95% CI: 2.29-6.51). One third reported receptive needle sharing at last injection. Factors independently associated with receptive needle sharing were years living in Tijuana (Adjusted Odds Ratio [AdjOR]= 0.97 per year, 95% CI: 0.96-0.99), being bisexual/homosexual (AdjOR=2.12; 95% CI: 1.30 - 3.44), unemployed (AdjOR=2.5; 95% CI: 1.52-4.10), never having an HIV test (AOR: 4.02; 95% CI: 2.44-6.60), having friends who placed importance on avoiding HIV (AdjOR: 0.36; 95% CI: 0.19-0.68) and last injecting in a shooting gallery (AdjOR=1.98; 95% CI: 1.21-3.24). These results underscore the need to increase access to voluntary HIV testing and counseling to IDUs and migrants in Tijuana, as well as expand access to sterile syringes in an effort to avert widespread HIV transmission.     

Barriers and missed opportunities to HIV testing among injection drug users in two Mexico--US border cities

INTRODUCTION AND AIMS: Despite increasing HIV prevalence in cities along the Mexico--US border, HIV testing among high-risk populations remains low. We sought to identify barriers associated with HIV testing among injection drug users (IDUs) in Tijuana and Ciudad Juarez, the two largest Mexican border cities located across from San Diego, California and El Paso, Texas, respectively. DESIGN AND METHODS: In 2005, 222 IDUs in Tijuana and 205 IDUs in Ciudad Juarez were recruited by respondent-driven sampling and administered a questionnaire to collect socio-demographic, behavioural and HIV testing history data. Blood samples were provided for serological testing of HIV, hepatitis C virus (HCV) and syphilis. RESULTS: Only 38% and 30% of respondents in Tijuana and Ciudad Juarez, respectively, had ever had an HIV test. The factors independently associated with never having been tested for HIV differed between the two sites, except for lack of knowledge on HIV transmission, which was independently associated in both locales. Importantly, 65% of those who had never been tested for HIV in both cities experienced at least one missed opportunity for voluntary testing, including medical visits, drug treatment and spending time in jail. DISCUSSION AND CONCLUSIONS: Among this high-risk IDU population we found HIV testing to be low, with voluntary testing in public and private settings utilised inadequately. These findings underscore the need to expand voluntary HIV education and testing and to integrate it into services and locales frequented by IDUs in these Mexico--US border cities.