Incidence of subarachnoid haemorrhage: a systematic review with emphasis on region, age, gender and time trends.

BACKGROUND AND AIM: To update our 1996 review on the incidence of subarachnoid haemorrhage (SAH) and assess the relation of incidence with region, age, gender and time period. METHODS: We searched for studies on the incidence of SAH published until October 2005. The overall incidences with corresponding 95% confidence intervals were calculated. We determined the relationship between the incidence of SAH and determinants by means of univariate Poisson regression. RESULTS: We included 51 studies (33 new), describing 58 study populations in 21 countries, observing 45,821,896 person-years. Incidences per 100,000 person-years were 22.7 (95% CI 21.9 to 23.5) in Japan, 19.7 (18.1 to 21.3) in Finland, 4.2 (3.1 to 5.7) in South and Central America, and 9.1 (8.8 to 9.5) in the other regions. With age category 45-55 years as the reference, incidence ratios increased from 0.10 (0.08 to 0.14) for age groups younger than 25 years to 1.61 (1.24 to 2.07) for age groups older than 85 years. The incidence in women was 1.24 (1.09 to 1.42) times higher than in men; this gender difference started at age 55 years and increased thereafter. Between 1950 and 2005, the incidence decreased by 0.6% (1.3% decrease to 0.1% increase) per year. CONCLUSIONS: The overall incidence of SAH is approximately 9 per 100,000 person-years. Rates are higher in Japan and Finland and increase with age. The preponderance of women starts only in the sixth decade. The decline in incidence of SAH over the past 45 years is relatively moderate compared with that for stroke in general.

Diagnostic value of high-resolution sonography in ulnar neuropathy at the elbow.

OBJECTIVE: To determine the diagnostic value of high-resolution sonography in ulnar neuropathy at the elbow (UNE). METHODS: Sonographic ulnar nerve diameter measurement was compared at three levels around the medial epicondyle with a criterion standard including clinical and electrophysiologic characteristics in a cohort of 123 patients presenting with clinical signs of UNE. UNE or probable UNE was diagnosed in 84 patients and a different condition in 39 patient controls. Reference values were obtained in 56 healthy volunteers. RESULTS: One hundred thirty-six affected arms were studied in 123 patients (UNE in 82, probable UNE in 9, and a different condition in 45 affected arms). Patients with UNE had a larger ulnar nerve diameter than patient controls (p < 0.0001). The sensitivity of sonography was 80%, specificity 91%, positive likelihood ratio 9, and negative likelihood ratio 0.2. The highest diagnostic yield was found in patients in whom electrodiagnostic studies showed signs of ulnar neuropathy but could not localize the lesion (17/20 cases, 86%) and in patients who had motor conduction velocity slowing across the elbow without conduction block (32/37 cases, 86%). CONCLUSIONS: High-resolution sonography is an accurate and easily applied test for the diagnosis of UNE. The authors recommend its use in addition to electrodiagnostic studies because it improves the reliability of the diagnosis of UNE.

Matrix methods for solving protein substructures of chlorine and sulfur from anomalous data.

The weak signal obtained from the anomalous scattering (at lambda = 1.54 A) of naturally occurring elements such as sulfur, phosphorus and ordered solvent chloride ions is used to determine the atomic positions of these atoms. Two examples are discussed: the sulfur and chlorine substructure of tetragonal hen egg-white lysozyme and an oligonucleotide containing ten P atoms. The substructure of lysozyme was also solved from Cu K(alpha) radiation data collected on a standard rotating-anode generator. The results presented here are an illustration of the power of the matrix methods, which are to be implemented in next distribution of the direct methods package CRUNCH.

Establishing a campylobacter-free pig population through a top-down approach.

Fattening pigs are often infected with campylobacter. To eliminate campylobacter from the pig population, a top-down approach, involving the breeding and reproduction farms, seems appropriate. In order to investigate the effectiveness of a top-down approach, sows' faeces from the following farms were analysed for the presence of campylobacter: one specific pathogen free (SPF) farm, three top-breeding farms with no connection with SPF breeding, and a breeding farm repopulated with SPF sows after a period of vacancy (farm 5). The faeces samples from the SPF farm were free from campylobacter. The three top-breeding farms provided faeces samples which were 98% positive for campylobacter. However, only 22% of the faeces samples from farm 5 were positive for campylobacter. In a period of 20 months, the percentage of sows infected with campylobacter on farm 5 did not significantly increase. Genetic typing with ERIC-PCR and RFLP of campylobacter isolates from one of the top-breeding farms and from farm 5 showed a high diversity of campylobacter types. The results suggest that a campylobacter-free pig population can be established in breeding farms by combining a top-down approach (campylobacter-free top-breeding farms) with a strict regime of hygiene management.

Computer-assisted analysis and epidemiological value of genotyping methods for Campylobacter jejuni and Campylobacter coli.

For epidemiological tracing of the thermotolerant Campylobacter species C. jejuni and C. coli, reliable and highly discriminatory typing techniques are necessary. In this study the genotyping techniques of flagellin typing (flaA typing), pulsed-field gel electrophoresis (PFGE), automated ribotyping, and amplified fragment length polymorphism (AFLP) fingerprinting were compared. The following aspects were compared: computer-assisted analysis, discriminatory power, and use for epidemiological typing of campylobacters. A set of 50 campylobacter poultry isolates from The Netherlands and neighboring countries was analyzed. Computer-assisted analysis made cluster analysis possible and eased the designation of different genotypes. AFLP fingerprinting was the most discriminatory technique, identifying 41 distinct genotypes, while PFGE identified 38 different types, flaA typing discriminated 31 different types, and ribotyping discriminated 26 different types. Furthermore, AFLP analysis was the most suitable method for computer-assisted data analysis. In some cases combining the results of AFLP fingerprinting, PFGE, and flaA typing increased our ability to differentiate strains that appeared genetically related. We conclude that AFLP is a highly discriminatory typing method and well suited for computer-assisted data analysis; however, for optimal typing of campylobacters, a combination of multiple typing methods is needed.

Complement-resistant Moraxella catarrhalis forms a genetically distinct lineage within the species.

Moraxella catarrhalis is a bacterial species that has been implicated in 15-20% of all cases of otitis media in the USA and the complement-resistant variant of M. catarrhalis has been considered particularly pathogenic. A collection of geographically diverse, complement-sensitive (n=28) and -resistant strains (n=47) of M. catarrhalis was assembled in order to analyse the bacterial population structure. All strains were identified as M. catarrhalis by conventional microbiological and biochemical methods. Amplification of the small subunit (ssu) ribosomal RNA gene followed by restriction fragment length polymorphism (RFLP) analysis did not reveal consistent differences between serum-susceptible and -resistant M. catarrhalis isolates. Interestingly, upon automated ribotyping using the Qualicon RiboPrinter(R) microbial characterisation system, the complement-sensitive and -resistant strains segregated into two groups. This suggested the existence of two clearly distinguishable lineages within the species M. catarrhalis. This observation was corroborated by pulsed field gel electrophoresis (PFGE) of DNA macro-restriction fragments, a non-ribosomal PCR RFLP procedure and random amplification of polymorphic DNA (RAPD) analysis. All procedures grouped the two variants similarly. Redefinition of the taxonomic status of complement-resistant M. catarrhalis or even the definition of a new species may be opportune.

Campylobacter infections in fattening pigs; excretion pattern and genetic diversity.

The excretion of campylobacter by eight individually housed fattening pigs was monitored during 15 weeks. Rectal faeces samples were collected six times from these pigs and twice from their mothers (seven sows). Campylobacter was cultured from these samples on Preston medium. In some pigs, samples positive for campylobacter alternated with negative samples. Campylobacter was detected in at least four of the six samples collected per fattening pig. The average campylobacter count per sampling showed a decreasing trend (P < 0.001). Of the seven sows, six were shown to excrete campylobacter. Campylobacter isolates of pigs and sows were typed using the Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR); 28 different campylobacter types were distinguished. Up to five different types were isolated from single faeces samples. Individual porkers could harbour up to eight types during their fattening period. The three types most frequently isolated from the fattening pigs were also present in the sows.

Reduction of campylobacter infections in broiler flocks by application of hygiene measures.

Transmission routes of Campylobacter spp. in broilers and possibilities for prevention of infections were studied on two Dutch broiler farms. The occurrence of Campylobacter spp. was studied in successive broiler flocks, in the environment of the farms and in some of the parent flocks involved. Isolates of Campylobacter spp. were typed by using randomly amplified polymorphic DNA (RAPD) analysis. The results indicate that broiler flocks become infected from environmental sources. The typing results suggest that on one farm transmission of Campylobacter spp. occurred from cattle to broilers via the farmer's footwear. After several campylobacter positive broiler cycles hygiene measures, including thorough cleaning and disinfection procedures, change of footwear at the entrance of each broiler house, control of vermin and other hygienic precautions, were introduced on both farms in order to prevent transmission of Campylobacter spp. from the farm environment to the broilers. The results indicate that the application of hygiene measures significantly reduced campylobacter infections of broiler flocks on both farms.

[Benign paroxysmal positional vertigo]. / Benigne paroxismale positieduizeligheid.

Benign paroxysmal positional vertigo is a common malfunction of the labyrinth, most frequently of the posterior canal, due to clot of debris in the endolymph. The attacks of vertigo are characterised by dependency on position, latency after positioning of the head, short duration, nystagmus, reversibility and fatiguableness. The diagnosis can be based on history, physical examination and provocative tilting of the head as described by Dix and Hallpike. In a typical case further investigations are not necessary. The symptoms often improve spontaneously. Half of the patients can be cured directly by stepwise tilting. This probably removes the clot from the canal of the labyrinth to the utriculus. Specific positional exercises also often have a good result, but not as quickly. Drug therapy has no place in the treatment.

Campylobacter hyoilei Alderton et al. 1995 and Campylobacter coli Véron and Chatelain 1973 are subjective synonyms.

The taxonomic affiliation of Campylobacter hyoilei was reevaluated by examining a variety of phenotypic and genotypic criteria. Whole-cell protein electrophoresis and a comparison of 66 phenotypic characters revealed that reference strains of C. hyoilei were indistinguishable from Campylobacter coli strains. These data were confirmed by a DNA-DNA hybridization level of 67% between the type strains of the two species. Several species-specific assays based on PCR amplification or probe hybridization further substantiated that C. coli strains and C. hyoilei strains are indistinguishable. It is therefore concluded that C. hyoilei and C. coli represent the same species and that the former name should be regarded as a junior synonym of the latter name.

The transmission of campylobacter in piggeries; an epidemiological study.

The campylobacter infection of 10 sows and their piglets was monitored. These pigs were kept on two multiplier farms. Rectal faeces samples were taken from the sows shortly before littering and at different intervals after littering. Swab samples of rectal content were taken from six piglets per sow at different intervals after birth. Nine sows were shown to be infected with campylobacter before litter and all sows after litter, with an average colony count of 4.1 in log N g-1 of faeces. Half of the piglets became infected with campylobacter during the first week of life and 85%, after four weeks. Two genetic subtyping methods (ERIC-PCR and RFLP) were used to study the relationships between campylobacter isolates from sows and piglets. A large diversity of campylobacter subtypes was found. Nevertheless, piglets and their mothers often harboured campylobacter isolates with identical genetic subtyping profiles, suggesting that piglets become infected via their mothers. However, observed similarities in genetic subtyping profiles between campylobacters isolated on different farms made this difficult to prove.

Electrophysiological analysis of midbrain periaqueductal gray influence on cardiovascular neurons in the ventrolateral medulla oblongata.

Stimulation of sites in the rostral or caudoventral periaqueductal gray (PAG) results in substantial increases in mean blood pressure (MBP) and heart rate (HR). The efferent pathways from these PAG subregions possibly include a relay in the ventrolateral medulla oblongata (VLM), where neurons involved in maintaining vasomotor tone are located. Extracellular recordings were made from 21 cardiovascular neurons in the rostral VLM (RVLM) and from 6 cardiovascular neurons in the caudal VLM (CVLM) of the rat. These neurons showed barosensitivity and cardiac rhythmicity. In addition, the activity of 54 non- cardiovascular and nonrespiratory units was recorded. Responses to electrical stimulation of sites in the (rostral or caudal) PAG were studied in 16 of the 21 cardiovascular RVLM neurons, the 6 CVLM neurons, and 46 of the 54 noncardiovascular neurons. Eight of the RVLM neurons were excited by rostral PAG stimulation; the poststimulus time histograms showed a constant latency in live units (32 +/- 3 ms). This suggests the presence of relatively direct (although not monosynaptic) excitatory pathways from the rostral PAG to cardiovascular neurons in the RVLM, consisting of slowly conducting fibers (0.2-0.3 m/s). Five RVLM neurons did not respond to rostral PAG stimulation. Three units were tested with caudal PAG stimulation: one was excited, one inhibited, and one was unresponsive. The six cardiovascular CVLM neurons did not respond to PAG stimulation. Of the 46 noncardiovascular neurons, 14 cells were excited, 7 inhibited, and 2 cells antidromically activated. These results confirm earlier findings, extending them to the rostral PAG. They supply further evidence for the influence of the PAG on the cardiovascular function-related neuronal circuitry in the VLM.

Cardiovascular effects and changes in midbrain periaqueductal gray neuronal activity induced by electrical stimulation of the hypothalamus in the rat.

The effects of low-intensity electrical stimulation of sites in the hypothalamus and zona incerta (ZI) on mean blood pressure (MBP), heart rate (HR), and neuronal activity in the midbrain periaqueductal gray (PAG) were investigated in rats. Long-lasting depressor responses were elicited from 67 sites in the hypothalamus and ZI. Effects on HR were variable, except for the ZI where bradycardiac responses were evoked. The amplitude of the depressor responses was significantly correlated with baseline MBP on stimulation of the dorsomedial hypothalamic nucleus (DMH) or the dorsal hypothalamic area. Extracellular single-unit recordings were made from 94 PAG neurons. Most units were located in the ventral half of the PAG (62/94), where spontaneous firing rates were significantly higher than in the dorsal half: 12.5 +/- 1.4 spikes/s as compared to 6.0 +/- 0.9 spikes/s. Changes in PAG neuronal activity to both ipsi- and contralateral hypothalamic stimulation were observed. Most neurons were inhibited or unresponsive. There was no site specificity: responsive and unresponsive neurons were scattered throughout the PAG. Inhibition was most effectively evoked by stimulation of the DMH (25 out of 39 neurons) and the ZI (9 out of 15 neurons). In most neurons, the inhibition strictly followed the time course of hypothalamic stimulation. The results suggest that PAG as well as nonPAG pathways participate in the hypothalamic control of cardiovascular function.

Microbes in food processing technology.

There is an increasing understanding that the microbial quality of a certain food is the result of a chain of events. It is clear that the microbial safety of food can only be guaranteed when the overall processing, including the production of raw materials, distribution and handling by the consumer are taken into consideration. Therefore, the microbiological quality assurance of foods is not only a matter of control, but also of a careful design of the total process chain. Food industry has now generally adapted quality assurance systems and is implementing the Hazard Analysis Critical Control Point (HACCP) concept. Rapid microbiological monitoring systems should be used in these cases. There is a need for rapid and simple microbiological tests which can be adapted to the technology and logistics of specific production processes. Traditional microbiological methods generally do not meet these high requirements. This paper discusses the tests, based on molecular biological principles, to detect and identify microbes in food-processing chains. Tests based on DNA technology are discussed, including in vitro DNA amplification like the polymerase chain reaction (PCR) method and identifications based on RFLP, RAPD and DNA fingerprinting analysis. PCR-based methodology can be used for the rapid detection of microbes in food manufacturing environments. In addition, DNA fingerprinting methods are suitable for investigating sources and routes of microbial contamination in the food cycle.

Prevalence of campylobacter in pigs during fattening; an epidemiological study.

Numerous epidemiological reports implicate foods of animal origin as vehicles of human campylobacteriosis. Pigs are probably an important reservoir of campylobacter and a potential source of human infection. In order to improve our knowledge of the epidemiology of campylobacter in pigs, the prevalence of campylobacter and its contamination of feed were monitored in eight pig farms. Faeces samples of pigs aged 11 and 22 weeks, and samples of rectal, ileal and gastric content at a slaughterhouse were collected for bacteriological examination. On 5 farms, subsequent groups of pigs housed in the same stalls was sampled, too. A selection of the campylobacter isolates was characterized with a genetic typing method (RFLP). More than 85% of the sampled porkers were shown to be intestinal carriers of campylobacter at all stages of fattening. Subsequent groups of pigs housed in the same stalls were all carriers, too. The level of campylobacters in the faeces tended to decrease as the pigs got older. There was no difference in the frequency and level of infection with campylobacter between porkers on different farms. The feeding system (wet feed versus dry pellets) did not seem to influence the prevalence of campylobacter although wet feed gave lower counts of Enterobacteriaceae in the faeces. RFLP-typing showed a high diversity of campylobacter strains at each sampling on the farm. Similarities were seen between strains isolated during two subsequent samplings of the same group of pigs, but not between strains isolated on the same farm from subsequent groups of pigs housed in the same stall. This suggests that the piglets were already infected at a young age on the breeding farm.

Development of species-specific DNA probes for Campylobacter jejuni, Campylobacter coli, and Campylobacter lari by polymerase chain reaction fingerprinting.

The application of polymerase chain reaction (PCR) fingerprinting assays enables discrimination between species and strains of microorganisms. PCR primers aiming at arbitrary sequences in combination with primers directed against the repetitive extragenic palindrome (REP) or enterobacterial repetitive intergenic consensus (ERIC) motifs generate isolate-specific DNA banding patterns. Analysis of these PCR fingerprints obtained for 33 isolates of Campylobacter jejuni, 30 isolates of Campylobacter coli, and 8 isolates of Campylobacter lari revealed that besides generation of isolate-specific fragments, species-specific DNA fragments of identical size were synthesized. It appeared that these DNA fragments could be used as species-specific probes, since they are unique for the pattern which they are deriving from. The probes do not cross-react with amplified DNA originating from a large panel of nonrelated microorganisms. Moreover, these probes displayed species specificity, as they reacted with a single restriction fragment on Southern blots containing DNA from C. jejuni, C. coli, and C. lari and other Campylobacter species. This combination of PCR fingerprinting and probe hybridization results in a highly specific identification assay and provides an example of specific test development without the prior need for DNA sequence information. The principle of the procedure holds great promise for the rapid isolation of DNA probes which, in combination with a general PCR assay, may lead to efficient typing and detection procedures for a multitude of medically important nonviral microorganisms.

Isolated profundaplasty in critical limb ischaemia--still of any use?

Because of the improved quality of peripheral bypass surgery, the role of isolated profundaplasty in revascularisation of the critically ischaemic limb has become very limited. This retrospective study of 72 isolated profundaplasties performed for critical limb ischaemia revealed a clinical improvement 1 year postoperatively of 39% in the period 1978-1983 and of only 9% between 1984-1990. In the total period, patient survival after 1 year was 81% and limb salvage 60%. Clinical, haemodynamic and arteriographic parameters were analysed for their predictive value of clinical success. The presence of tissue necrosis or ulceration (clinical stage IV) affected clinical outcome negatively (p < 0.05). Risk factors and indicators for arteriosclerotic disease, age of the patient and ankle-brachial systolic pressure index (ABI) had no significant predictive value. Evaluation of the preoperative arteriographies revealed that only the aspect of the profunda femoris artery beyond its orifice was of significance: there was a strong relationship between the absence of obstructive disease in this part of the artery and clinical improvement (p < 0.005). These two significant parameters may be guidelines when considering an isolated profundaplasty as an alternative in the treatment of critical limb ischaemia. However, in the presence of other treatment possibilities nowadays, especially bypass surgery, the procedure appears to offer a very poor success rate.

Factors determining the outcome of crural and pedal revascularisation for critical limb ischaemia.

The influences of clinical factors, site of distal anastomosis, type of graft and angiographic run-off, on graft patency and limb salvage following 141 femorocrural and pedal bypasses in 121 patients were investigated retrospectively. The grafts consisted of 111 femorocrural and 30 pedal bypasses; 49% of the patients had diabetes mellitus. Venous grafts were implanted in 116 limbs, using either in situ vein (65), reversed vein (38) or composite vein (13) graft. Twenty-five prosthetic grafts (14 PTFE and 11 umbilical veins) were inserted. After 1, 2, 3 and 4 years of follow-up, the primary cumulative patency rates for all grafts were respectively 67, 61, 55 and 55%, and the secondary patency rates were 75, 70, 64 and 64%. The site of distal anastomosis had no influence on graft patency rate; neither was there any significant effect of clinical risk factors and run-off on graft patency. Prosthetic grafts showed significantly lower patencies compared to venous grafts and appeared to be the only independent prognostic risk factor for graft failure (multivariate analysis; p = 0.03). Overall limb salvage rate was 84% at 3 years. There were four amputations with patent grafts. The limb salvage rates for in situ vein, reversed/composite vein and prosthetic grafts were 89, 79 and 66% at 3 years, respectively. Various bypass grafts to the crural and pedal arteries are successful and durable. The use of prosthetic grafts results in significantly lower patency rates, but appears to be effective for limb salvage.