Global transcriptomic analysis in avocado nursery trees reveals differential gene expression during asymptomatic infection by avocado sunblotch viroid (ASBVd)

Avocado sunblotch viroid (ASBVd) is the type species of the family Avsunviroidae and the causal agent of avocado sunblotch disease. The disease is characterised by the presence of chlorotic lesions on avocado fruit, leaves and/or stems. Infected trees may remain without chlorosis for extended periods of time, though distorted growth and reduced yield has been observed in these cases. The molecular effects of ASBVd on avocado, and members of the Avsunviroidae on their respective hosts in general, remain poorly understood. Host global transcriptomic studies within the family Pospiviroidae have identified several host pathways that are affected during these plant-pathogen interactions. In this study, we used RNA sequencing to investigate host gene expression in asymptomatic avocado nursery trees infected with ASBVd. Transcriptome data showed that 631 genes were differentially expressed, 63 % of which were upregulated during infection. Plant defence responses, phytohormone networks, gene expression pathways, secondary metabolism, cellular transport as well as protein modification and degradation were all significantly affected by ASBVd infection. This work represents the first global gene expression study of ASBVd-infected avocado, and the transcriptional reprogramming observed during this asymptomatic infection improves our understanding of the molecular interactions underlying broader avsunviroid-host interactions.

A revised description of Synodontella zambezensis Douëllou et Chishawa, 1995 (Monogenea: Ancyrocephalidae) from the gills of Synodontis zambezensis (Siluriformes: Mochokidae) from South Africa

This study supplements the original description of Synodontella zambezensis Douëllou et Chishawa, 1995 and represents a new geographical record for this parasite from Synodontis zambezensis from South Africa. The revision is based on morphometric characteristics and molecular data. Characterisation of LSU, partial SSU and ITS1 rDNA represents a first record of DNA sequencing for Synodontella species.

Local Intraarterial Thrombolysis in the Carotid Territory

A new series of 142 patients treated by local intraarterial thrombolysis is presented. After haemorrhage was ruled out by CT, all patients had an emergency angiogram. Patients with occlusion of the lenticulostriate arteries were not treated after the sixth hour (79 cases). Patients without involvement of these arteries were treated up to the 12th hour (61 cases).

This selection led to a dramatic reduction of pos-thrombolysis intraparenchymatous haemorrhage (0.7%) compared to other series. All deaths (7 cases) were related to vasogenic oedema due to incomplete reduction of infarcted cerebral volume, in most cases (4 cases) in intracerebral extension of a cervical internal carotid occlusion.

Digitized parenchymography proved to be a reliable technique to document the exact location and extent of brain ischaemia before and after thrombolysis. It also allows a prognosis of spontaneous recovery without using thrombolysis. By reducing the infarcted cerebral volume, local intraarterial thrombolysis seems beneficial to the patient as long as a strict selection based on the angiographic location of the occlusion and the time delay is respected.

Seasonal occurrence of some larval stages of endoparasites in three cyprinids from the Nwanedi-Luphephe dams, the Limpopo River System, South Africa

This study provides information on seasonal occurrence of developmental stages of endoparasites infecting three cyprinids in the Nwanedi-Luphephe dams, Limpopo River System. Labeobarbus marequensis (Smith, 1841), Barbus trimaculatus Peters, 1852 and Barbus radiatus Peters, 1853 were investigated seasonally from January 2008 to October 2008. The following larvae of metazoan parasites were collected: Diplostomum sp. from the eyes of L. marequensis and B. trimaculatus; Ornithodiplostomum sp. from the gills of B. trimaculatus; Posthodiplostomum sp. from muscle, skin and fins of B. trimaculatus and B. radiatus; third-stage Contracaecum larvae (L3) from the mesentery fats and on the liver lobes of L. marequensis and B. trimaculatus and gryporynchid cestode larvae from the outer intestinal wall of B. radiatus. All the flukes encountered were metacercariae. Diplostomum sp. and Contracaecum sp. dominated the parasite communities. Their prevalence exhibited seasonal fluctuations with maxima in summer. Factors likely to influence fish infection such as the body size of fish and their condition factors were also briefly considered in this study.

Predicting antigenic sites on the foot-and-mouth disease virus capsid of the South African Territories types using virus neutralization data

Foot-and-mouth disease virus (FMDV) outer capsid proteins 1B, 1C and 1D contribute to the virus serotype distribution and antigenic variants that exist within each of the seven serotypes. This study presents phylogenetic, genetic and antigenic analyses of South African Territories (SAT) serotypes prevalent in sub-Saharan Africa. Here, we show that the high levels of genetic diversity in the P1-coding region within the SAT serotypes are reflected in the antigenic properties of these viruses and therefore have implications for the selection of vaccine strains that would provide the best vaccine match against emerging viruses. Interestingly, although SAT1 and SAT2 viruses displayed similar genetic variation within each serotype (32 % variable amino acids), antigenic disparity, as measured by r(1)-values, was less pronounced for SAT1 viruses compared with SAT2 viruses within our dataset, emphasizing the high antigenic variation within the SAT2 serotype. Furthermore, we combined amino acid variation and the r(1)-values with crystallographic structural data and were able to predict areas on the surface of the FMD virion as antigenically relevant. These sites were mostly consistent with antigenic sites previously determined for types A, O and C using mAbs and escape mutant studies. Our methodology offers a quick alternative to determine antigenic relevant sites for FMDV field strains.

Study on the efficacy and safety of different antigens and oil formulations of infectious coryza vaccines containing an NAD-independent strain of Avibacterium paragallinarum

The present study was designed to assess and compare three different formulations of the new Onderstepoort infectious coryza (IC) quadrivalent vaccine, which contain an NAD-independent strain of Avibacterium paragallinarum (previously known as Haemophilus paragallinarum), and a commercial IC vaccine, not containing an NAD-independent strain, for their safety and ability to protect chickens of varying ages against virulent challenges with four different serovars of A. paragallinarum, including the NAD-independent strain of the C-3 serovar. Four groups of 140 chickens each were vaccinated at the age of 17 weeks and revaccinated at the age of 19 weeks with each of the four vaccine formulations. A similar sized group of non-vaccinated chickens was used as control. Two rounds of challenge were conducted: a group of chicken in each vaccination group was challenged between 31 and 35 weeks of age, while another group was challenged between 51 and 55 weeks of age. The "in-contact" challenge model was used in this experiment. For each vaccination group, the four challenge strains representing four local serovars were used in each challenge round. The efficacy of the vaccines was compared based on overall protection levels obtained and the duration of protection. The safety of the different vaccines was determined by the severity of post-vaccination reactions. The need for the incorporation of the NAD-independent strain in the vaccine was evidenced by the low protection level against NAD-independent challenge recorded in the group of birds vaccinated with the commercial vaccine. The results obtained confirmed not only the variation in virulence of different South African serovars, with serovar C-3 being the most virulent and serovar B having almost no virulence but also the age related increase in susceptibility. The importance of a suitable formulation of the vaccine is discussed.

Direct percutaneous venous puncture and embolization of giant perimedullary arteriovenous fistulas

PMAVFs are rare entities that are formed by a direct communication between an artery that feeds the spinal cord and a vein. The goal of treatment is to occlude the shunt; this is done endovascularly either from an arterial or a venous approach. When these approaches are not possible, direct percutaneous puncture of the draining veins may be attempted to embolize the arteriovenous shunt directly.

Percutaneous treatment of cervical disk hernias using gelified ethanol

This study investigates the efficacy of chemonucleolysis using RGE in the treatment of cervical disk hernias in a small sample of patients who had cervical diskogenic or radicular pain secondary to disk herniations. Results were satisfactory in 89.5% patients, with no adverse events recorded during the procedure or after. The use of RGE shows promising results and might be a feasible and safe alternative in the treatment of cervical disk hernias.

Nanotechnology and water treatment: applications and emerging opportunities

Nanotechnology, the engineering and art of manipulating matter at the nanoscale (1-100 nm), offers the potential of novel nanomaterials for treatment of surface water, groundwater, and wastewater contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms. Due to their unique activity toward recalcitrant contaminants and application flexibility, many nanomaterials are under active research and development. Accordingly, literature about current research on different nanomaterials (nanostructured catalytic membranes, nanosorbents, nanocatalysts, and bioactive nanoparticles) and their application in water treatment, purification and disinfection is reviewed in this article. Moreover, knowledge regarding toxicological effects of engineered nanomaterials on humans and the environment is presented.

Cloning and characterization of a 4-hydroxyphenylacetate 3-hydroxylase from the thermophile Geobacillus sp. PA-9

A 4-hydroxyphenylacetic acid (4-HPA) hydroxylase-encoding gene, on a 2.7-kb genomic DNA fragment, was cloned from the thermophile Geobacillus sp. PA-9. The Geobacillus sp. PA-9 4-HPA hydroxylase gene, designated hpaH, encodes a protein of 494 amino acids with a predicted molecular mass of 56.269 Da. The deduced amino-acid sequence of the hpaH gene product displayed <30% amino-acid sequence identity with the larger monooxygenase components of the previously characterized two-component 4-HPA 3-hydroxylases from Escherichia coli W and Klebsiella pneumoniae M5a1. A second oxidoreductase component was not present on the 2.7-kb genomic DNA fragment. The deduced amino-acid sequence of a second C-terminal truncated open reading frame, designated hpaI, exhibited homology to extradiol oxygenases and displayed the highest amino-acid sequence identity (43%) with the 3,4-dihydroxyphenylacetate 2,3-dioxygenase of Arthrobacter globiformis, encoded by mndD. These results, along with catalytic activity observed in crude intracellular extracts prepared from Escherichia coli cells expressing hpaH, is in support of a role for hpaH in the 4-HPA degradative pathway of Geobacillus sp. PA-9.

Management of spinal dural arteriovenous fistulae with emphasis on an endovascular approach

Spinal arteriovenous shunts are rare and present at a rate of approximately 1:10 with cerebral arteriovenous shunts. Spinal dural arteriovenous fistulas (SDAVF) are the most common type of spinal vascular malformation in the adult and account for about 60% of all, with a marked male predominance (5:1). Endovascular treatment has gained force as the treatment of choice in recent years. We reviewed the patients sent to our service at Clinica del Rosario in Madrid and Hospital General de Cataluña in Barcelona between January 1991 and December 2005 with a diagnosis of SDAVF made clinically or by imaging for possible endovascular treatment. Location, presenting symptoms, and clinical outcome according to treatment were analyzed. A total of 104 patients were diagnosed and treated for a SDAVF, 85 were men and 19 women aged between 23 and 79 years (average 58). Seventy-six were treated with embolization alone (73%), 21 with a combination of endovascular therapy and surgery (20.1%) and seven patients had surgery alone (6.7%). Of the embolization group, 62 patients were cured (81.5%), 11 improved (14.4%) and three (3.9%) worsened. Of the group with combined therapy, 13 (61.9%) were cured, five (23.8%) improved and three (14.2%) worsened. Among the surgery group, four (57.2%) were cured and three (42.8%) worsened. Endovascular approach with liquid adhesive is gaining more acceptance as the treatment of choice for SDAVF if the conditions allow a super selective catheterization of the shunt. These patients benefit most when diagnosis is made early in the course of the pathology and have a better chance of a complete remission of symptoms.

A second RGD motif in the 1D capsid protein of a SAT1 type foot-and-mouth disease virus field isolate is not essential for attachment to target cells

The amino acid sequence motif Arg-Gly-Asp (RGD), located in the surface-exposed betaG-betaH loop of the 1D protein of different serotypes and subtypes of foot-and-mouth disease virus (FMDV), is highly conserved and participates in binding of FMDV to susceptible cells. Previous sequence analyses of the 1D-encoding region of a FMDV serotype SAT1 field isolate from Namibia (NAM/307/98) indicated the presence of a second RGD motif upstream of the conserved betaG-betaH loop RGD. The role of these RGD sequences in virus infection was investigated by mutating the betaG-betaH loop RGD to a KGE tripeptide, using a genome-length infectious chimeric cDNA clone. Although the infectivity of the derived mutant viruses for baby hamster kidney cells (BHK-21) was lost, subsequent replacement of the KGE sequence with RGD in the mutant cDNA clone led to recovery of infectious viruses. Furthermore, viral RNA replication could be demonstrated with the genetically engineered mutant and non-mutant viruses. The presence of virus particles in the transfected cells could be also demonstrated by electron microscopy. These results demonstrate that, in contrast to the betaG-betaH loop RGD motif, the second RGD sequence in the capsid protein 1D of NAM/307/98 does not function as a ligand for receptor binding in BHK-21 cells.

Ultrasound-assisted transthoracic biopsy: fine-needle aspiration or cutting-needle biopsy?

The present study compared the diagnostic yield of ultrasound-assisted cutting-needle biopsy (CNB) and fine-needle aspiration biopsy (FNAB) in chest lesions. A physician performed ultrasound and FNAB with a 22-G spinal needle in all patients, directly followed by a 14-G CNB in patients without contraindication. A total of 155 consecutive lesions arising from the lung (74%), pleura (12%), mediastinum (11%) or chest wall (3%) in patients with a final diagnosis of lung carcinoma (74%), other malignant tumours (12%), non-neoplastic disease (9%) or unknown (5%) were prospectively included. The overall diagnostic yield was 87%. Combined specimens were obtained in 123 lesions (79%). In these, yields of FNAB, CNB and both methods combined were 82, 76 and 89%, respectively. FNAB was significantly better than CNB in lung carcinoma (95 versus 81%) but CNB was superior in noncarcinomatous tumours and in benign lesions. On-site cytology was 90% sensitive and 100% specific for predicting a positive FNAB. One patient required drainage for pneumothorax (0.6%). Ultrasound-assisted fine-needle aspiration biopsy performed by chest physicians is an accurate and safe initial diagnostic procedure in patients with a high clinical probability of lung carcinoma. All other patients should undergo concurrent fine-needle aspiration biopsy and cutting-needle biopsy.

Transbronchial needle aspirates: how many passes per target site?

Transbronchial needle aspiration is a bronchoscopic sampling method for a variety of bronchial and pulmonary lesions. The present study investigated whether and how serial needle passes contribute to the yield of transbronchial needle aspiration at specific target sites. A total of 1,562 needle passes, performed at 374 target sites in 245 patients with neoplastic disease (82%), non-neoplastic disease (15%) or undiagnosed lesions (3%), were prospectively recorded and rated for anatomical location, size, bronchoscopic appearance and underlying disease. Positive aspirates were obtained in 75% of patients and at 68% of target sites. A diagnosis was established with the first, second, third and fourth needle pass at 64, 87, 95 and 98% of targets, respectively. The absolute yield varied strongly with target site features, but the stepwise increment to the maximum yield provided by serial passes was similar across target sites. In conclusion, three transbronchial needle passes per site are appropriate when only a tissue diagnosis is sought and when alternative sites or sampling modalities are available. At least four or five passes should be carried out at lymph node stations critical for the staging of lung cancer.

Segment specific inverted repeat sequences in bluetongue virus mRNA are required for interaction with the virus non structural protein NS2

Computational secondary structure prediction of all 10 Bluetongue virus (BTV-10) RNA transcripts and mutant inverted repeat transcripts were performed. Transcripts with intact 5' and 3' inverted repeat sequences, all indicated base-pairing between the 5' and 3' ends when optimal folding parameters were applied. Secondary structure analysis of the mutant transcripts lacking the inverted repeat sequences indicated alterations in the secondary structures resulting from altered base-pairing. The importance of the inverted repeat sequences in RNA--protein binding was subsequently investigated. Deletion mutant clones lacking the 5' and/or 3' inverted repeat sequences have been constructed. A baculovirus recombinant expressing the BTV NS2 protein and radioactively synthesized RNA transcripts were subjected to nitrocellulose RNA--protein binding assays. The cumulative results suggested that the inverted repeat deletion mutants display weaker binding compared to BTV-10 segment 8 with intact 5' and 3' inverted repeat sequences. Inverted repeats may influence RNA--protein binding by altering the secondary structure of the RNA and consequently the specific NS2 protein-binding sites may no longer be available.

Safety and Yield of Ultrasound-Assisted Transthoracic Biopsy Performed by Pulmonologists

BACKGROUND

Transthoracic ultrasound (US) has gained popularity as a tool for visualizing pleural effusions and assisting thoracentesis or chest drain placement. In the absence of effusion, US just as well demonstrates solid masses involving or abutting the pleura, yet biopsy of such lesions is not widely performed by chest physicians.

OBJECTIVE

To assess the feasibility and the safety of US-assisted cutting needle biopsy performed by chest physicians in routine practice.

METHODS

Lesions involving or abutting the pleura > or =20 mm in diameter on US were sampled with a 14-gauge cutting needle under local anesthesia. Biopsy site, needle direction and depth of penetration were determined with US. The procedure was performed without direct US guidance in 'free-hand' technique.

RESULTS

Ninety-one patients underwent 96 cutting-needle biopsies for suspected peripheral lung tumors (n = 44, 46%), pleural-based (n = 39, 41%), mediastinal (n = 10, 10%), or chest wall lesions (n = 3, 3%), which were single in 71%, multiple in 6% and diffuse in 23%. Sensitivity for malignant neoplasms (n = 65) was 85.5% and 100% for mesothelioma (n = 10). Pneumothorax occurred in 4%.

CONCLUSIONS

US-assisted cutting-needle biopsy of lesions > or =20 mm in diameter is safe in the hands of pulmonologists. The yield for neoplastic disease including mesothelioma is high.

The occurrence of campylobacters in water sources in South Africa

Campylobacter spp., mainly C. jejuni and C. coli, are recognized as significant human bacterial pathogens, being responsible for increasing numbers of gastroenteritis cases worldwide. Several reports have indicated that environmental waters are potential reservoirs and transmitting vehicles for these bacteria. The purpose of this study was thus to examine the occurrence of campylobacters in drinking and environmental water sources of South Africa, a country with a warmer climate and higher microbial pollution levels than those previously addressed in the Northern Hemisphere where similar investigations have been undertaken. Various types of water samples (five drinking water, four ground water, 11 surface water and four raw sewage) were collected from different parts of South Africa. Detection was by enrichment in Bolton broth prior to plating on both selective mCCDA or through a 0.6microm membrane filter on non-selective blood agar isolation media. Out of 100 initially selected Campylobacter-like isolates, only 22 did not grow aerobically and were subsequently identified as Campylobacter spp. by biochemical tests. However, the results obtained by 16S rRNA sequence analysis indicated that only three of these strains (13.6%) were Campylobacter jejuni and the remaining 19 strains were identified as Arcobacter butzleri. The spread of Arcobacter via water warrants further investigation, especially in view of the higher levels of detection and pathogenic nature of these bacteria.

[Endovascular treatment of a cervical vertebral artery pseudoaneurysm using covered stents. One case report]

Covered stents have been successfully used in the treatment of fusiform aneurysms and post dissection aneurysms in peripheral arteries as well as in post-traumatic arteriovenous fistulas. We report a case where a pseudoaneurysm of the cervical vertebral artery was excluded by placement of two covered stents, preserving patency of the parent artery, in a 15-year-old patient.

Emerging waterborne infections: contributing factors, agents, and detection tools

Because microorganisms are easily dispersed, display physiological diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in water. The presence of waterborne enteric pathogens (bacteria, viruses, and protozoa) in domestic water supplies represents a potentially significant human health risk. Even though major outbreaks of waterborne disease are comparatively rare, there is substantial evidence that human enteric pathogens that are frequently present in domestic water supplies are responsible for low-level incidence of waterborne microbial disease. Although these diseases are rarely debilitating to healthy adults for more than a few hours to a few days, enteric pathogens can cause severe illness, even death, for young children, the elderly, or those with compromised immune systems. As the epidemiology of waterborne diseases is changing, there is a growing global public health concern about new and reemerging infectious diseases that are occurring through a complex interaction of social, economic, evolutionary, and ecological factors. New microbial pathogens have emerged, and some have spread worldwide. Alternative testing strategies for waterborne diseases should significantly improve the ability to detect and control the causative pathogenic agents. In this article, we provide an overview of the current state of knowledge of waterborne microbial pathogens, their detection, and the future of new methods in controlling these infectious agents.

Early surgical treatment of Cyrano-nose haemangiomas with Rethi incision

Nasal haemangiomas may cause great social distress. Complete involution of these haemangiomas does not usually result in a return to normality. The subcutaneous tumour infiltrates the alar cartilages, resulting in a globular aspect of the nasal tip. In this location, haemangiomas are slow to regress, and contour deformities result from the fibrofatty tissue that remains after total involution and also from definitive deformation of the nasal cartilages. Surgery to remove the affected tissue and preserve the anatomy seems to be the best treatment for these tumours. We report six cases of nasal haemangiomas removed using the Rethi incision and a double rim incision. This procedure allows complete dissection of the tumour, and leaves only a small scar. The alar cartilages are returned to their anatomical position to allow normal growth. Surgery is performed at around 2 years of age; skin excision is not necessary because spontaneous skin retraction occurs. Our patients were evaluated by their parents, the surgeon and members of the dermatology staff not involved in their treatment. Pain, scar and final aspect were evaluated using statistical analysis. The parents and surgeon rated the postoperative results as very satisfactory or satisfactory. The dermatology staff also reported improvement after surgery. The scar is nearly invisible and the procedure allows excision of large nasal haemangiomas.

Evaluation of a novel heminested PCR assay based on the phosphoglucosamine mutase gene for detection of Helicobacter pylori in saliva and dental plaque

A novel heminested PCR protocol was developed for the specific detection of Helicobacter pylori at low copy numbers. A set of primers specific for the phosphoglucosamine mutase gene (glmM) of H. pylori produced a 765-bp fragment that was used as template for the heminested primer pair delineating a 496-bp fragment. By using agarose gel electrophoresis for detection of the heminested PCR-amplified products, amplification of H. pylori genomic DNA was achieved at concentrations as low as 0.1 pg, equivalent to 5 x 10(2) bacteria. A study was subsequently undertaken to evaluate the heminested PCR for detection of H. pylori in dental plaque and saliva. Specimens collected from 58 individuals were cultured, and PCR was subsequently performed on the oral cultures. Identification of H. pylori in the same series of saliva and dental plaque specimens was carried out with PCR using a primer pair specific for the H. pylori urease B gene and by the heminested PCR assay. The identity of the amplified products was confirmed by DNA sequencing. Our results demonstrate that the heminested PCR assay was specific for detection of H. pylori, yielding no false-positive results, and that H. pylori had a low prevalence (approximately 3%) in specimens obtained from the oral cavity.

Mucous membrane pemphigoid: HLA-DQB1*0301 is associated with all clinical sites of involvement and may be linked to antibasement membrane IgG production

BACKGROUND

Class I human leucocyte antigens (HLA) -A, -B, -Cw and class II HLA-DRB1, -DQB1 alleles were determined in 131 British Caucasian patients with mucous membrane pemphigoid (MMP) using serological and DNA-based methods.

OBJECTIVES

To analyse the class I and II alleles expressed in well-defined clinical and immunopathological subgroups of MMP, in order to establish whether specific alleles or haplotypes might in part explain disease susceptibility, clinical sites of involvement or disease severity.

METHODS

Subgroups of patients were analysed according to the following clinical criteria: age of onset, sex, sites of clinical involvement (oral, ocular, skin, nasal, genital, pharyngeal, oesophageal, laryngeal, perianal), disease severity and history of autoimmune disease. Subgroups were also analysed according to the following immunopathological criteria: autoantibody profile, the presence of circulating antibasement membrane IgG or IgA antibodies and the detection of target basement membrane zone (BMZ) antigens (BP230 and BP180) by IgG autoantibodies.

RESULTS

Class I HLA typing showed no significant disease or subgroup associations. Class II DRB1 typing showed a significantly increased allelic frequency in MMP vs. controls for DRB1*11 (RR = 2.08, Pc < 0.0000056). For DQB1, MMP vs. controls, there was a significantly increased allelic frequency for DQB1*0301 (Pc < 0.00000028) in both males and females; all clinical sites of involvement, with the exception of laryngeal, oesophageal and perianal sites and in patients with detectable circulating anti-BMZ IgG compared with those negative for IgG (P < 0.0096, Pc < 0.019). A positive trend was noted in patients with ocular involvement compared with no ocular involvement and in patients with a clinical score > or = 10 compared with < 10. We found no difference in DQB1*0301 allele frequency between subgroups with or without BP180 or BP230 target antigens. Haplotype frequencies showed an increase in DRB1*04, DQB1*0301 (Pc < 0.000066) and DRB1*11, DQB1*0301 (Pc < 0.000002) among patients compared with controls.

CONCLUSIONS

The DQB1*0301 allele confers a predisposition to all subgroups of MMP and may have a role in T-cell recognition of basement membrane antigens, resulting in the production of anti-BMZ IgG autoantibodies. The positive trend between increased allelic expression of DQB1*0301 in patients with ocular disease and in those with a higher clinical score, further suggests a role for this allele in disease severity.

The use of glass wool as an attachment surface for studying phenotypic changes in Pseudomonas aeruginosa biofilms by two-dimensional gel electrophoresis

Two-dimensional polyacrylamide gel electrophoresis was used to demonstrate phenotypic differences between Pseudomonas aeruginosa biofilm cells and the planktonic counterpart cells under defined culture conditions. Glass wool was used as a substratum for cell attachment as it affords a large surface-to-volume ratio (1 g with a mean diameter of 15 microns = 1300 cm2), supports the growth of biofilms, allows for free movement of cells between the inter-strand spaces, and it facilitates the exchange of nutrients and oxygen. It also allows for the separation of the biofilm biomass from the surrounding surface influenced planktonic (SIP) cells for further characterization. Comparative analysis of the respective proteomes indicated striking differences in the protein patterns of planktonic, biofilm and SIP cells. We selected 41 proteins, the levels of which varied in a significant and reproducible way in the respective protein profiles. In the biofilm cells, a general up-regulation of the spots was seen, but in SIP cells expression of these spots were generally down-regulated. Altogether six unique proteins were seen in the planktonic cells, while the biofilm and SIP cells contained five and two unique proteins, respectively. Glass wool, therefore, appears to be an ideal attachment surface for the study of biofilm development.

Cervical automated discectomy. Report of 150 cases and evolution in the management of failure cases

SUMMARY

The lumbar automated discectomy system described by Onik has been used in the treatment of cervical disk herniations whose symptomatology resisted medical treatment. Experience on 150 patients is reported showing a 74.5% success rate. This series performed in most cases on an outpatient basis had no complications. Up to 1992 failure cases were treated by intradiscal injections of triamcinolone with 62 % of success. This complementary technique was abandonned after the description of epidural calcifications secondary to this type of injections in the lumbar area. Since 1992, failure cases have been managed differently with injections of steroids in the cervical joints, especially when a hypertrophy of the ligamentum ftavum supposedly a sign of an inflammatory posterior component of the pain was demonstrated on the CT. Nine patients received intradiscal injections of microdoses (600IU) of chymopapaine with excellent results. No patient has had open surgery since 1992. It is concluded that percutaneous automated discectomy is a very promising and safe technique which can be used as a first choice technique for most cervical disk herniations resisting medical treatment.

A sensitive seminested PCR method for the detection of Shigella in spiked environmental water samples

A rapid seminested polymerase chain reaction (PCR) method for the specific, sensitive detection of virulent Shigella spp. in spiked environmental water samples was developed. A set of primers specific for the invasion plasmid antigen gene (ipaH) of virulent Shigella spp. and enteroinvasive Escherichia coli produced a 620-bp fragment that was used as template for the seminested primer pair delineating a 401-bp fragment. By using agarose gel electrophoresis for detection of the seminested PCR-amplified products, a detection limit of 1.6 x 10(3) cfu S. flexneri was obtained with amplification reactions from crude bacterial lysates. The PCR procedure coupled with an enrichment culture incubated for 6 h detected as few as 1.6 S. flexneri organisms in pure culture. Treated sewage, ground, surface and drinking water samples collected from various sources were seeded with S. flexneri and incubated in GN broth for 6 h before detection by seminested PCR. A detection limit lower than 14 cfu/ml was achieved in some water samples. The results indicate that the described seminested PCR has the advantage of a rapid turnaround time and it fulfills the requirements of sensitivity and specificity for use in an environmental laboratory.

Current status of carotid bifurcation angioplasty and stenting based on a consensus of opinion leaders

OBJECTIVE

Carotid bifurcation angioplasty and stenting (CBAS) has generated controversy and widely divergent opinions about its current therapeutic role. To resolve differences and establish a unified view of CBAS' present role, a consensus conference of 17 experts, world opinion leaders from five countries, was held on November 21, 1999.

METHODS

These 17 participants had previously answered 18 key questions on current CBAS issues. At the conference these 18 questions and participants' answers were discussed and in some cases modified to determine points of agreement (consensus), near consensus, (prevailing opinion), or divided opinion (disagreement).

RESULTS

Conference discussion added two modified questions, placing a total of 20 key questions before the participants, representing four specialties (interventional radiology, seven; vascular surgery, six; interventional cardiology, three; neurosurgery, one). It is interesting that consensus was reached on the answers to 11 (55%) of 20 of the questions, and near consensus was reached on answers to 6 (30%) of 20 of the questions. Only with the answers to three (15%) of the questions was there persisting controversy. Moreover, both these differences and areas of agreement crossed specialty lines. Consensus Conclusions: CBAS should not currently undergo widespread practice, which should await results of randomized trials. CBAS is currently appropriate treatment for patients at high risk in experienced centers. CBAS is not generally appropriate for patients at low risk. Neurorescue skills should be available if CBAS is performed. When cerebral protection devices are available, they should be used for CBAS. Adequate stents and technology for performing CBAS currently exist. There were divergent opinions regarding the proportions of patients presently acceptable for CBAS treatment (<5% to 100%, mean 44%) and best treated by CBAS (<3% to 100%, mean 34%). These and other consensus conclusions will help physicians in all specialties deal with CBAS in a rational way rather than by being guided by unsubstantiated claims.

Detection of toxigenic Vibrio cholerae from environmental water samples by an enrichment broth cultivation-pit-stop semi-nested PCR procedure

A pit-stop semi-nested PCR assay for the detection of toxigenic Vibrio cholerae in environmental water samples was developed and its performance evaluated. The PCR technique amplifies sequences within the cholera toxin operon specific for toxigenic V. cholerae. The PCR procedure coupled with an enrichment culture detected as few as four V. cholerae organisms in pure culture. Treated sewage, surface, ground and drinking water samples were seeded with V. cholerae and following enrichment, a detection limit of as few as 1 V. cholerae cfu ml(-1) was obtained with amplification reactions from crude bacterial lysates. The proposed method, which includes a combination of enrichment, rapid sample preparation and a pit-stop semi-nested PCR, could be applicable in the rapid detection of toxigenic V. cholerae in environmental water samples.

Molecular techniques for determining microbial diversity and community structure in natural environments

The ability to quantify the number and kinds of microorganisms within a community is fundamental to the understanding of the structure and function of an ecosystem. The simple morphology of most microbes provides few clues for their identification and physiological traits are often ambiguous. In addition, many organisms resist cultivation, which is essential to their characterization. Recombinant DNA techniques have provided a means whereby many of the obstacles associated with cultivation and description can be overcome and subsequently has allowed many new insights into the complexity of natural microbial communities. Molecular approaches based on 16S ribosomal RNA (rRNA) sequence analysis allow direct investigation of the community structure, diversity, and phylogeny of microorganisms in almost any environment, while quantification of the individual types of microorganisms or entire microbial communities may be addressed by nucleic acid hybridization techniques. Furthermore, the use of fluorescently labeled population-specific rRNA probes allows microscopic examination of individual cells in complex microbial assemblages as well as their interactions in situ. In this review, we discuss strategies for characterizing microbial communities without the need for cultivation.

Atrophy of the corpus callosum correlates with white matter lesions in patients with cerebral ischaemia

Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, mid-anterior and mid-posterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and mid-anterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia.

Distal Flow Protection during Carotid Stenting

This study was conducted to evaluate presence of embolic debris during ICA stent procedures. Nine patients with severe carotid atheromatous stenosis were treated by stent implantation under distal flow protection using a non-detachable balloon.

After stent implantation, the lumen of the ICA was cleaned by aspiration of 50 cc of blood before further flush cleaning and deflation of the protection balloon.

The blood samples obtained from each patient were analyzed using a microscope to check quantity and aspect of embolic debris. Significant numbers of embolic debris were recovered from blood samples in all nine stenting cases, but very few were found in four out of the five control cases. This observation demonstrates the high risk of producing embolic debris during carotid stenting. Distal balloon occlusion and cleaning procedures are techniques to provide protection from thromboembolic complications to the brain.

The occurrence of Theileria and Cowdria parasites in African buffalo (Syncerus caffer) and their associated Amblyomma hebraeum ticks

The polymerase chain reaction and oligonucleotide probing were used to detect Theileria and Cowdria species in DNA extracted from blood and ticks recovered from 24 African buffalo during a gamecapture operation in the Kruger National Park, South Africa. Species-specific probing indicated that all but one of the buffalo were carrying at least one Theileria species. Indirect fluorescent antibody (IFA) serology indicated that all animals had been exposed to Theileria parva infection but only 33% were positive for T. parva by probing. Twelve (50%) of the animals but only six of the 214 adult Amblyomma hebraeum ticks examined (2.8%) were probe-positive for Cowdria. Only one Cowdria 16S genotype was detected in the animals and ticks.

Non-penetrating subclavian artery trauma: management by selective transluminally placed stent device

Non-penetrating injury to the subclavian artery has not often been reported. The limited experience of surgeons with this type of trauma and the difficult vascular control required for its management make it a surgical challenge. We report on two cases, one after blunt trauma and the other with a subclavian artery aneurysm following anterior dislocation of the shoulder. Percutaneous stent implantation in the subclavian artery was successfully performed with, in the second case, coil embolization of the aneurysm. Follow-up Doppler sonography and angiogram demonstrated patency and luminal integrity of the involved artery. This less invasive procedure may be a significant advance and a new approach in the conservative management of traumatic subclavian injury for selected cases.

Towards a molecular phototyping system for allelic variants of MICA, encoded by polymorphisms in exons 2, 3 and 4 of MHC class I chain-related genes

In this study we have developed a polymerase chain reaction-sequence-specific primer (PCR-SSP) or phototyping system to analyse the polymorphism of the human MICA gene locus. By scrutinising the reported MICA sequence variations in exons 2, 3 and 4 which encode the extracellular protein domains, we have selected and tested 20 MICA-specific primer mixes that should discriminate between the majority of homozygous and heterozygous combinations of MICA alleles 001-016. We have tested this scheme on DNA prepared from a large number of well-characterised tissue culture cell lines with previously reported MICA nucleotide sequences and found an excellent correlation with the observed PCR-SSP phototypes. We believe that this scheme can also be modified to detect new MICA alleles when they are characterised, as well as be incorporated into standard phototyping protocols to generate allele and haplotype profiles of both classical and non-classical HLA gene loci in test DNA samples.

Complications of carotid angioplasty and stenting

The authors report the complications that occurred in their experience with performing recanalization procedures in the internal carotid artery and present their treatment strategies. The complications can be classified into those that were periprocedural and those that were postprocedural. The former include complications related to the vascular-approach access site of and those associated with the dilation and stenting procedure. Other complications observed included embolic events, dissection, vascular spasm, bradycardia, inappropriate dilation, occlusion of the external carotid artery, and rare, unusual complications such as the occurrence of iatrogenic cavernous carotid fistula. Postprocedure complications occurred in the hours and days following the procedure in the form of embolic and occlusive events, and hypotension and bradycardia were seen as late complications in the months following the procedure. The authors discuss how such complications occur and provide suggestions on how to avoid them. The role of stent placement and the potential use of protective devices are explored. Overall, adequate use of currently available systems allows for safe application of endovascular treatment techniques that avoid altogether or treat these potential complications. A reduced incidence of complications related to the initial individual learning curve may be obtained with preclinical training, in which use of invitro models should be considered. Surgical standby no longer seems required; however, early posttreatment surveillance in intensive care unit is mandatory to avoid the remaining primary complications.