Evaluation of the BAX system for detection of Listeria monocytogenes in foods: collaborative study

A multilaboratory study was conducted to compare the automated BAX system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.

Are physiotherapy graduates adequately prepared to to manage hiv/aids patients

Physiotherapy learners treat patients with Human Immuno-deficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS). There is no available published research on physiotherapy learners' opinions about how the South Afican physiotherapy undergraduate program is  helping them cope with HIV/AIDS patients. This study determines whether the physiotherapy degree offered at South African Universities, adequately prepares learners to cope with HIV/AIDS patients. Differences in knowledge and attitudes of physiotherapy learners regarding HIV/AIDS, amongst  universities is also explored. Two hundred and two senior physiotherapy learners from eight South African universities returned their  questionnaires and 55% of these were viable for analysis. A large portion (79%) of learners indicated that the physiotherapy undergraduate degree did not adequately prepare them to cope with HIV/AIDS patients. Learners' knowledge and attitudes regarding HIV/AIDS differed significantly (41% to 73%)  amongst universities. Formal lectures on HIV/AIDS significantly affected knowledge (0% -100%) but not attitude towards patients. The role of the physiotherapist, precautions, transmission modes, syndrome stages, counseling and clinical skills were considered critical in the management of HIV/AIDS patients.

Genetic diversity and virulence gene determinants of antibiotic-resistant Salmonella isolated from preharvest turkey production sources

This study evaluated the molecular diversity of 29 Salmonella serotypes isolated from turkey ceca and the production environment. Isolates were resistant to bacitracin (100%), erythromycin (100%), novobiocin (100%), rifampin (100%), streptomycin (62%), gentamicin (52%), spectinomycin (48%), tetracycline (31%), sulfamethoxazole/trimethoprim (SXT) (3%) and tobramycin (3%). The minimum inhibitory concentration (MIC) values ranged from 32 to >/=1024 microg/ml. The pulsed-field gel electrophoresis (PFGE) and ribotyping patterns were identical within each of the serotypes Heidelberg, Worthington and Muenster. The plasmid profiles were identical within each of the Salmonella serotypes. Two different clones of Salmonella anatum were differentiated by PFGE typing but not by ribotyping. Heidelberg isolates from nine turkey ceca and three drinker samples had identical antibiotic resistance, PFGE, ribotype and plasmid patterns, suggesting that transmission of this particular clone may have occurred between the birds and the drinkers. Identical PFGE, ribotype and plasmid patterns were observed in one Salmonella worthington isolate from turkey ceca in one flock and two S. worthington isolates from feeder contents and drinkers from a subsequent flock, suggesting transmission of this pathogen between flocks. Individual and multiple polymerase chain reaction (PCR) analyses revealed the presence of the virulence genes invA, aceK and sopB and the absence of the h-1i gene in all isolates. A combination of genotypic and phenotypic markers can be useful in studying genetic variation among natural salmonellae populations in turkey production and delineating possible transmission pathways.

The role of aquatic ecosystems as reservoirs of antibiotic resistant bacteria and antibiotic resistance genes

The widespread and indiscriminate use of antibiotics has led to the development of antibiotic resistance in pathogenic, as well as commensal, microorganisms. Resistance genes may be horizontally or vertically transferred between bacterial communities in the environment. The recipient bacterial communities may then act as a reservoir of these resistance genes. In this study, we report the incidence of antibiotic resistance in enteric bacteria isolated from the Mhlathuze River and the distribution of genetic elements that may be responsible for the observed antibiotic resistance. The resistance of the enteric bacteria isolated over a period of one year showed that resistance to the older classes of antibiotics was high (94.7% resistance to one antibiotic and 80.8% resistance to two antibiotics). Furthermore, antibiotic resistance data of the environmental isolates showed a strong correlation (r = 0.97) with data obtained from diarrhoea patients. PCR based methods demonstrated that class 1 integrons were present in >50% of the environmental bacterial isolates that were resistant to multiple antibiotics. This class of integrons is capable of transferring genes responsible for resistance to beta-lactam, aminoglycoside, sulfonamide and quaternary ammonium antimicrobial agents. Conjugate plasmids were also isolated, but from a small percentage of isolates. This study showed that the Mhlathuze River (a) is a medium for the spread of bacterial antibiotic resistance genes, (b) acts as a reservoir for these genes and (c) due to socio-economic pressures, may play a role in the development and evolution of these genes along this river system.

Effects of strapping the tendo-Achilles

SA Sports Medicine Vol.15(2) 2003: 9-13

Volleyball injuries in KwaZulu-Natal - epidemiology

SA Sports Medicine Vol.15(3) 2003: 26-28

Concentric sclerosis: imaging diagnosis and clinical analysis of 3 cases

Baló's Concentric sclerosis (BCS) is a rare demyelinating disease considered to be a variant of multiple sclerosis (MS). The typical magnetic resonance imaging (MRI) changes associated with BCS consist of concentric rings or onions' cross-section on T1-weighted (T1W) images. Because MRI reveals pathological changes consistent with autopsy in the focus of BCS, it plays an important role in the before-death diagnosis of BCS. We report three cases of BCS diagnosed antemortem on the basis of the typical concentric rings pattern on MRI and on the basis of clinical findings and cerebrospinal fluid (CSF) examination. BCS often occurs in the prime of life, acutely or subacutely. Then come cerebral multifocal symptoms and signs. We find that BCS is not always an acute and irreversible pathological process as described in the past.

[Exogenous nitric oxide induces apoptosis in tachyzoites of Toxoplasma gondii]

OBJECTIVE

To explore whether NO is able to induce apoptosis in Toxoplasma gondii tachyzoites.

METHODS

Apoptosis induced by NO in T. gondii tachyzoites was investigated by TUNEL (terminal-deoxynucleotidyl transferase mediated d-UTP nick end labeling) method, electron microscopy and agarose gel electrophoresis.

RESULTS

NO donor, sodium nitroprusside (SNP), was found to induce apoptosis in Toxoplasma gondii tachyzoites in a time- and dose-dependent manner by TUNEL detection. N-acetylcysteine, a NO scavenger, could inhibit SNP-induced apoptosis in the tachyzoites while potassium ferricyanide could not induce apoptosis in the tachyzoite. Electron macroscopy showed that SNP-treated tachyzoites possessed typical morphological features of apoptosis, including chromatin condensation below the nuclear membrane, nuclear pyknosis, and formation of apoptotic body. Agarose gel electrophoresis revealed that SNP-treated tachyzoite DNA fragment exhibited characteristic "DNA ladder" after 15 to 20 h.

CONCLUSION

SNP, NO donor, might induce apoptosis in T. gondii tachyzoites in terms of characteristic morphological and biochemical features.

Exogenous nitric oxide induces apoptosis in Toxoplasma gondii tachyzoites via a calcium signal transduction pathway

The mechanism by which nitric oxide (NO)-dependent cytotoxicity acts against Toxoplasma gondii tachyzoites is poorly understood. An NO donor, sodium nitroprusside (SNP), was used to induce death in T. gondii tachyzoites in vitro as a model for investigating (i) whether NO is capable of inducing apoptosis-like death in tachyzoites and (ii) whether a calcium signal transduction pathway is involved. Exposure to 2 mM SNP resulted in a pattern of tachyzoite death that shares many features with metazoan apoptosis and it may involve a calcium signal transduction pathway. Motility and cell survival in these parasites showed a gradual decline with increasing levels of SNP. Features common to metazoan apoptosis are observed after exposure to 2 mM SNP. Ethylene glycol bis-(beta-aminoethyl ether)-N,N,N',N'-tetra-acetic acid (EGTA), Verapamil and bis-(o-aminophenoxy) ethane-N,N,N',N'-tetra-acetic acid/acetoxymethyl ester (BAPTA/AM) partially increased the cell survival concomitant with decreased [Ca2+]i in cells exposed to SNP. An NO scavenger (N-acetylcysteine), the analogue of SNP (devoid of NO), inhibited the rate of apoptosis after SNP treatment compared with SNP treatment without scavenger, but alone did not induce apoptosis. Taken together, the results indicate that SNP is capable of inducing apoptosis in T. gondii tachyzoites via a calcium signal transduction pathway.

[Taxonomic studies on Echinochasmus fujienensis and its related species by random amplified polymorphic DNA analysis and experimental infection]

AIM

To explore the identification and differentiation of Echinochasmus fujianensis, Echinochasmus japonicus(Jiangxi strain and Fujian strain), Echinochasmus liliputanus Anhui and Echinochasmus per foliatus Hubei.

METHODS

Random amplified polymorphic DNA analysis (RAPD) and experimental animal infection were performed.

RESULTS

469 polymorphic DNA fragments were obtained by 28 primers from 4 Echinochasmus species and strains in Fujian, Anhui and Jiangxi. 20.8% and 97.6% of the fragments in Echinochasmus fujianensis were the same as those in Echinochasmus japonicus Fujian strain and in Echinochasmus liliputanus Anhui, respectively, 99.7% of the fragments were the same between Echinochasmus japonicus Jiangxi strain and Fujian strain.

CONCLUSION

Echinochasmus fujianensis and Echinochasmus liliputanus Anhui are the same species. Echinochasmus fujienensis is an independent species different from Echinochasmus japonicus. Polyinfection of Echinochasmus fujianensis, Echinochasmus japonicus and Echinochasmus perfoliatus exist in all the 3 provinces, Hubei, Anbui and Fujian, of which Echinochasmus fujienensis is a dominant species.

[Preliminary study on the levels of natural antibodies against Schistosoma japonicum in Microtus fortis in Dongting lake area]

AIM

To explore the detection rate and the levels of natural antibodies to cercarial antigen(CA), juvenile antigen(JA), adult worm antigen (AWA) and soluble egg antigen (SEA), respectively, derived from Schistosoma japoncum in Microtus fortis distributed in Dongting Lake area.

METHODS

The antibodies in wild Microtus fortis(WMF), laboratory-bred Microtus fortis (BMF) and laboratory-bred Microtus fortis 15 days after S. japonicum infection (BMFi15) were detected by indirect ELISA and a comparison of the antibody levels between Microtus fortis including WMF, BMF, BMFi15 and albino mice without infection (AM), 15 days after infection(AMi15) and 42 days after infection (AMi42) was made.

RESULTS

The positive rates of detection for anti-JA-Ab in WMF and BMF were 94.6% and 94.4%, respectively, followed by 85.5% and 83.3% for anti-AWA-Ab, 58.1% and 59.4% for anti-SEA-Ab, and 14.3% and 13.9% for anti-CA-Ab. The levels of antibodies to the above four antigens in BMFi15 increased significantly, the detection rates being 100% for anti-JA-Ab and anti-AWA-Ab, 84.4% for anti-SEA-Ab and 65.6% for anti-CA-Ab. The levels of antibodies in WME, BMF and BMFi15 had the similar trend(JA > AWA > SEA > CA), and those in BMFi15 to CA, JA, AWA and SEA increased by 1.9, 2.2, 2.1 and 1.5 folds, respectively, when compared with BMF.

CONCLUSION

Natural antibodies to Schistosoma japonicum were found in wild and labortorybred Microtus fortis. The levels of antibodies in BMFi15 to four above antigens were apparently higher than those in AMi15.

Growth hormone releasing factor decreases long form leptin receptor expression in porcine anterior pituitary cells

Pituitary cells from six pigs, 180-200 days of age, were studied in primary culture to determine if growth hormone releasing factor (GRF) affects long form leptin receptor (Ob-Rl) expression. On Day 4 of culture, 10(5) live cells per well were challenged with either 0, 10(-6), 10(-7) or 10(-8)M [Ala15]-hGRF-(1-29)NH(2) (3 wells per treatment per pig). Secretion of growth hormone (GH) into the media and pituitary Ob-Rl mRNA expression were determined at 4 h after treatment. Media were analyzed for GH by radioimmunoassay, and total RNA was isolated from cells for determination of Ob-Rl expression by semi quantitative reverse transcription PCR. Basal GH concentration was 32+/-2 ng per 10(5) cells per well (n=18 wells) for 4 h. Relative to control at 4 h, 10(-6),10(-7) and 10(-8)M GRF increased (P<0.01) GH secretion by 151, 129 and 120%, but decreased (P<0.05) Ob-Rl expression by 32, 50 and 38%, respectively. These results indicate that GRF directly modulates Ob-Rl expression at the level of the pituitary, and thereby playing a role in regulating pituitary sensitivity to leptin.

Identification of a novel DPB1 allele, DPB1*9301, by sequence-based typing in a Lahu ethnic minority of China

A novel DPB1 allele (DPB1*9301) has been identified in an individual from the Lahu ethnic minority of China. Its sequence was confirmed by sequencing the PCR products and clones. This allele differs from DPB1*0601, *1701 and *3701 by two nucleotides in each, and results in amino acids substitution.

Identification of bulb from Fritillaria cirrhosa by PCR with specific primers

Bulb of Fritillaria cirrhosa is an important traditional Chinese herbal medicine. According to the Chinese Pharmacopoeia (1995), it is commonly used as an antitussive and expectorant. Many young bulbs from species of Fritillaria are similar to those of F. cirrhosa, but they are different in price and quality. Therefore, there are many young bulbs from species of Fritillaria that could fake those of F. cirrhosa on the commercial market. The coding region of 5S-rRNA is highly conserved in higher eukaryotes. The 5S-rRNA spacer region sequences of F. thunbergii, F. pallidiflora, F. ussuriensi, F. delavayi, F.cirrhosa, F. anhuiensis, F. puqiensis were cloned by PCR with a pair of primers located within the conserved coding region. Based on sequences analyses of the 5S-rRNA spacer region from the 7 species, a specific sequence was found in F. cirrhosa. A pair of specific primers was designed for differentiating the bulbs of F. cirrhosa from each other by PCR. This result indicated that the method is rapid, more accurate and applicable in identification of the bulbs of F. cirrhosa at the DNA level.

HLA-DRB1, DQB1 and DPB1 polymorphism in the Naxi ethnic group of South-western China

Polymorphism of HLA-DRB1, DQB1 and DPB1 was revealed with a sequencing-based typing (SBT) method in unrelated healthy volunteers from the Naxi ethnic group. Among the 43 DRB1 alleles detected, the most common allele was DRB1*12021 with a frequency of 17%, followed by DRB1*08032, DRB1*09012 and DRB1*1404 with frequencies of 8.5%, 7.4% and 7.4%, respectively. Among 23 DQB1 alleles detected, the most frequent DQB1 allele was DQB1*03011/0309 (21.9%), followed by DQB1*0502 (16.4%) and DQB1*05031 (9.6%). For the DPB1 locus, the most common alleles were DPB1*0501 (25.5%), DPB1*0402 (14.6%) and DPB1*02012 (12.0%). The most common DRB1-DQB1-DPB1 haplotype was DRB1*1404-DQB1*05031-DPB1*0402 with a frequency of 5.26%, followed by the DRB1*08032-DQB1*06011-DPB1*1301 (3.51%). The distribution characteristics of the HLA class II alleles revealed that the Naxi ethnic group belonged to the Southern group of Chinese.