Humoral responses in cattle to commercial vaccines containing Clostridium perfringens epsilon toxoid and C. botulinum types C and D toxoids last less than a-year

The aim of this study was to evaluate the titers of neutralizing antibodies in cattle inoculated with multivalent commercial clostridial vaccines containing C. botulinum type C (BoNTC), C. botulinum type D (BoNTD), and C. perfringens epsilon (ETX) toxoids for a period of one year. Cattle (Bos taurus), aged 4-6 months and not previously immunized, were vaccinated under four different protocols at days 0 and 30 and followed over one year. Individual serum titration was performed by a serum neutralization test in mice or in MDCK cells. The number of animals with detectable neutralizing antibodies ranged from 40.6% to 78.1%, but only 12.5% of animals showed neutralizing antibodies against all tested antigens. Neutralizing antibodies were found only until 60 days for ETX, 120 days for BoNTC, and 180 days for BoNTD. The absence of detectable neutralizing antibodies against the three antigens before 360 days, suggests that cattle remained unprotected for a long period before the recommended booster vaccination.

Comparison of humoral neutralizing antibody response in rabbits, guinea pigs, and cattle vaccinated with epsilon and beta toxoids from Clostridium perfringens and C. botulinum types C and D toxoids

Rabbits and guinea pigs are used in the official control and validation of clostridial vaccines, but it is unknown whether the antitoxin titers obtained in these animals corroborate with the humoral response in bovine. The objective of the study was to compare the humoral antibody response of guinea pig and rabbits to those obtained in cattle vaccinated with a commercial vaccine containing Clostridium perfringens epsilon and beta, and Clostridium botulinum types C and D toxoids. This study revealed the same level of humoral response in rabbits and cattle for all four toxoids tested, including C. botulinum types C and D toxoids. In contrast, the titers of neutralizing antibodies against C. botulinum type C toxin in guinea pigs differed from those obtained in cattle. Thus, the present work suggests that the potency test for C. botulinum types C in rabbits agrees more with the humoral response in cattle than the potency test in guinea pigs, thereby making it possible to use only rabbits as models in the official control and validations of clostridial vaccines.

Detection of toxins A/B and isolation of Clostridium difficile and Clostridium perfringens from dogs in Minas Gerais, Brazil

The objective of this study was to detect C. difficile A/B toxins and to isolate strains of C. perfringens and C. difficile from diarrheic and non-diarrheic dogs in Brazil. Stool samples were collected from 57 dogs, 35 of which were apparently healthy, and 22 of which were diarrheic. C. difficile A/B toxins were detected by ELISA, and C. perfringens and C. difficile were identified by multiplex PCR. C. difficile A/B toxins were detected in 21 samples (36.8%). Of these, 16 (76.2%) were from diarrheic dogs, and five (23.8%) were from non-diarrheic dogs. Twelve C. difficile strains (21.1%) were isolated, of which ten were A⁺B⁺ and two were A⁻B⁻. All non-toxigenic strains were isolated from non-diarrheic animals. The binary toxin gene cdtB was found in one strain, which was A⁺B⁺ and was derived from a non-diarrheic dog. C. perfringens strains were isolated from 40 samples (70.2%). Of these, 18 (45%) were from the diarrheic group, and 22 (55%) belonged to the non-diarrheic group. All isolates were classified as C. perfringens type A and there was an association between the detection of the cpe gene and the presence of diarrhea. Interestingly, ten strains (25%) were positive for the presence of the cpb2 gene. The high rate of detection of the A/B toxins in non-diarrheic dogs suggests the occurrence of subclinical disease in dogs or carriage of its toxins without disease. More studies are needed to elucidate the epidemiology of C. difficile and C. perfringens in dogs and to better our understanding of C. difficile as a zoonotic agent. This is the first study to report the binary toxin gene in C. difficile strains isolated from dogs in Brazil.

Expression of TERT in precancerous gastric lesions compared to gastric cancer

The objective of this study was to determine the levels of TERT mRNA and TERT protein expression in stomach precancerous lesions such as intestinal metaplasia (IM) and gastric ulcer (GU) and compare them to gastric cancer (GC). Real-time PCR was performed to detect TERT mRNA expression levels in 35 biopsies of IM, 30 of GU, and 22 of GC and their respective normal mucosas. TERT protein was detected by immunohistochemistry in 68 samples, 34 of IM, 23 of GU, and 11 of GC. Increased TERT mRNA expression levels were observed in a significant number of cases, i.e., 46% of IM, 50% of GU, and 79% of GC. The relative mean level of TERT mRNA after normalization with the β-actin reference gene and comparison with the respective adjacent normal mucosa was slightly increased in the IM and GU groups, 2.008 ± 2.605 and 2.730 ± 4.120, respectively, but high TERT mRNA expression was observed in the GC group (17.271 ± 33.852). However, there were no statistically significant differences between the three groups. TERT protein-positive immunostaining was observed in 38% of IM, 39% of GU, and 55% of GC. No association of TERT mRNA and protein expression with Helicobacter pylori infection or other clinicopathological variables was demonstrable, except for the incomplete type vs the complete type of IM. This study confirms previous data of the high expression of both TERT mRNA and protein in gastric cancer and also demonstrates this type of changed expression in IM and GU, thus suggesting that TERT expression may be deregulated in precursor lesions that participate in the early stages of gastric carcinogenesis.

Subgenotype diversity of hepatitis B virus American genotype F in Amerindians from Venezuela and the general population of Colombia

The objective of this study was the evaluation of the genetic diversity found in HBV circulating among Venezuelan Amerindians and the general population in Colombia. Phylogenetic analysis of the S region in 194 isolates showed that genotype F is highly predominant in Colombia and Venezuela. This might be related to the genetic background of the population. F3 is the main subgenotype which circulates in both countries. Phylogenetic analysis of 61 complete genome sequences of HBV American genotypes confirms the presence of two genotypes F and H, and 4 F subgenotypes. In Venezuela, subgenotypes F1, F2, and F3 circulate in East and West Amerindians, while only F3 was found among South Amerindians. Japreira community derived from Yucpa Amerindians around 150 years ago. However, several Japreira HBV sequences were forming a clade that can be classified as subgenotype 2b, differing from Yucpa sequences that belong mainly to subgenotype F3. The apparent absence of correlation between the phylogenetic groupings of HBV isolates with the ethnical origin in aboriginal populations might be suggesting a recent origin of HBV American subgenotypes, or a genetic drift effect.

Correlations between pulse oximetry and peak expiratory flow in acute asthma

Few studies are available concerning correlations between pulse oximetry and peak expiratory flow in children and adolescents with acute asthma. Although the Global Initiative for Asthma states that measurements of lung function and oximetry are critical for the assessment of patients, it is not clear if both methods should necessarily be included in their evaluation. Since there is a significant difference in cost between pulse oximetry equipment and peak expiratory flow devices, we determined whether clinical findings and peak expiratory flow measurements are sufficient to determine the severity of acute asthma. The present prospective observational study was carried out to determine if there is correlation between pulse oximetry and peak expiratory flow determination in 196 patients with acute asthma aged 4 to 15 years diagnosed according to the Global Initiative for Asthma criteria. Patients experiencing their first or second wheezing episode, with fever, related acute or chronic diseases, and unable to perform the peak expiratory flow maneuver were excluded. Measurements of peak expiratory flow and pulse oximetry were performed at admission and after 15 min of each inhaled salbutamol cycle. Correlations obtained by linear regression using the Pearson correlation coefficients (r) were 0.41 (P < 0.0001), 0.53 (P < 0.0001), 0.51 (P < 0.0001), and 0.61 (P < 0.0001) at admission and after the first, second and third cycles of salbutamol, respectively. These correlations showed that one measure cannot substitute the other (Pearson's coefficient <0.7), probably because they evaluate different aspects in the airways, suggesting that peak expiratory flow should not be used alone in the assessment of acute asthma in children and adolescents.

[Use of prophylactic medication in persistent asthma]

OBJECTIVE: To assess the proportion of patients with moderate or severe persistent asthma who are on prophylactic therapy when first evaluated at a specialized outpatient center. METHODS: Descriptive study of 306 patients with persistent asthma and ages ranging from four to fifteen years old, seen from June/1995 to August/1998, at the Respiratory and Allergic Diseases section of the Child and Adolescent Institute, an outpatient reference center located in the town of Juiz de Fora (MG), Brazil. Data from the Institute's registry, chiefly those related to the use of prophylactic medications, such as inhaled steroids, sodium chromoglycate, nedocromil sodium, sustained-release theophylline, long acting inhaled beta2-agonist and ketotifen were used to fill in a standardized protocol. RESULTS: Of the 306 patients, 87.3% had persistent moderate and 12.7% had persistent severe asthma. Only 14.4% were on some kind of controller medication. When only the use of inhaled antiinflammatory drugs (sodium cromolyn, nedocromil sodium and steroids) was considered, this proportion decreased to 4.6%. There was not statistical significance (p<0.05) between the use or not of prophylactic regimens in relation to gender, weight, height, asthma severity, hospital admissions, age of onset, age when first evaluated at the outpatient center and household smoking. CONCLUSIONS: The rate of utilization of prophylactic regimens in this population of persistent asthmatic patients was unsatisfactory, a finding particularly stressed by the low rate of subjects on inhaled antiinflammatory drugs. It is necessary to emphasize such measures to face the magnitude that asthma represents in our country.

Periprandial blood glucose and insulin values during the third trimester of normal pregnancies

In order to determine the normal periprandial blood glucose values during gravidity, we studied 17 normal pregnant women, near term of gestation, in their homes using test strips and reflectometers . Results show an initial fasting level not higher than 80 mg/dl and not lower than 45 mg/dl. In all cases but one blood glucose levels were lower than 120 mg/dl, irrespective of when the measurements were taken. Insulin determinations permitted us to recognize low and high responders, although no differences could be found between them.