Acute changes in the neuronal expression of GABA and glutamate decarboxylase isoforms in the rat piriform cortex following status epilepticus

The piriform cortex (PC) is the largest region of the mammalian olfactory cortex with strong connections to other limbic structures, including the amygdala, hippocampus, and entorhinal cortex. In addition to its functional importance in the classification of olfactory stimuli, the PC has been implicated in the study of memory processing, spread of excitatory information, and the facilitation and propagation of seizures within the limbic system. Previous data from the kindling model of epilepsy indicated that alterations in GABAergic inhibition in the transition zone between the anterior and posterior PC, termed here central PC, are particularly involved in the processes underlying seizure propagation. In the present study we studied alterations in GABAergic neurons in different parts of the PC following seizures induced by kainate or pilocarpine in rats. GABA neurons were labeled either immunohistochemically for GABA or its synthesizing enzyme glutamate decarboxylase (GAD) or by in situ hybridization using antisense probes for GAD65 and GAD67 mRNAs. For comparison with the PC, labeled neurons were examined in the basolateral amygdala, substantia nigra pars reticulata, and the hippocampal formation. In the PC of controls, immunohistochemical labeling for GABA and GAD yielded consistently higher neuronal densities in most cell layers than labeling for GAD65 or GAD67 mRNAs, indicating a low basal activity of these neurons. Eight hours following kainate- or pilocarpine-induced seizures, severe neuronal damage was observed in the PC. Counting of GABA neurons in the PC demonstrated significant decreases in densities of neurons labeled for GABA or GAD proteins. However, a significantly increased density of neurons labeled for GAD65 and GAD67 mRNAs was determined in layer II of the central PC, indicating that a subpopulation of remaining neurons up-regulated the mRNAs for the GAD isoenzymes. One likely explanation for this finding is that remaining GABA neurons in layer II of the central PC maintain high levels of activity to control the increased excitability of the region. In line with previous studies, an up-regulation of GAD67 mRNA, but not GAD65 mRNA, was observed in dentate granule cells following seizures, whereas no indication of such up-regulation was determined for the other brain regions examined. The data substantiate the particular susceptibility of the central PC to seizure-induced plasticity and indicate that this brain region provides an interesting tool to study the regulation of GAD isoenzymes.

Postoperative Wundinfektionen

Surgical site infections can be traced to discrepancies in one specific hospital department: the operating suite. Therefore, prevention is often viewed as resting completely on the surgeon. However, the source of micro-organisms responsible for surgical site infections can be endogenous or exogenous. Most infections are believed to be the former, i.e. caused by micro-organisms already resident in the patient's body. Therefore the surgeon can be regarded as suspect only in exceptional cases and usually himself a victim. Prevention is possible not only for exogenous surgical site infection but also many endogenous infections. A multicenter surveillance of infection rates at 130 operative departments participating for at least 4 years in the German National Nosocomial Infection Surveillance System was conducted. A significant 25% reduction in the 3rd year was observed compared with patients who underwent surgery within the 1st year of participation. However, surgeons alone cannot achieve such a decrease, and a team approach is required under most circumstances.

[Update on Bardet-Biedl syndrome]

Until recently, Bardet-Biedl syndrome was considered as a classic autosomal recessive condition. The disorder is defined by the association of the following clinical features: retinitis pigmentosa, polydactyly, obesity, hypogonadism, and possible mental retardation. This syndrome leads to multiple handicaps (visual impairment, complications of obesity, kidney failure, endocrine dysfunction). This condition, apparently clearly defined from a clinical point of view, appears to be genetically heterogenous. To date, six different genes have been identified: BBS1, BBS2, BBS4, BBS6, BBS7 and BBS8. Interestingly, this condition has recently been linked to a failure of cellular ciliogenesis. Moreover, this disorder is characterized by an additional degree of complexity, as it is the first example of triallelic inheritance described in human beings. However, this new finding appears to be less frequent than expected in this syndrome.

„Out-of-body experience“ als mögliches Anfallssymptom bei einem Patienten mit rechtsparietaler Läsion

Out-of-body experiences are reported in a variety of diseases and physiologic conditions. We report a 44-year-old patient with epigastric auras, psychomotor and grand mal seizures, and paroxysmal experiences during which he believed to have left his body and seen himself from the outside. Electroencephalography showed a right temporal and right parietal seizure pattern on several occasions, and a lesion in the right parietal lobe was detected by cranial magnetic resonance imaging. Histological examination showed a pleomorphic xanthoastrocytoma. Following extirpation of the lesion, the patient has been seizure-free for 5 years.

Reduction of orthopaedic wound infections in 21 hospitals

INTRODUCTION

The German national nosocomial infections surveillance system (KISS) has been collecting surveillance data from hip and knee prosthesis operations since 1997. The purpose of this article is to investigate whether surveillance and feedback of surgical site infection (SSI) information to the physicians and nurses of participating hospitals lead to reduced SSI rates or not.

MATERIALS AND METHODS

Only information from hospitals previously participating for at least 3 years was used for the analysis. Monthly SSI rates were pooled over the 36-month period, beginning in each clinic's case with its first month of participation, the rates then being compared for 12-month periods. Relative risks were calculated for comparison of the SSI rates in the first and third years of participation. A multiple logistic regression analysis with stepwise variable selection was performed to identify significant risk factors, including the year of surveillance after starting surveillance activities.

RESULTS

The overall SSI rates were 1.4% for hip prosthesis and 1.0% for knee prosthesis. Fourteen clinics participated in KISS for at least 3 years continuously with HIP prostheses and 21 with knee prostheses. It was possible to include a total of 15,457 hip and 9,011 knee procedures for this analysis. A comparison of data from the first and the third years show a significant SSI reduction with hip procedures, with a relative risk of 0.54 (CI95 0.38-0.77), and a trend towards reduced SSI rates for knee procedures. The multiple logistic regression analysis confirmed that the SSI rate for hip prosthesis was significantly lower in the third year than in the first year of surveillance (OR = 0.57; CI95 0.42-0.78), though for knee prosthesis the level of significance was not achieved.

CONCLUSION

A reduction of SSIs following hip and knee prosthesis operations through the introduction of ongoing surveillance and the possibility of using benchmark data for comparison does seem to be possible in many institutions.

[Spontaneous gas gangrene in a diabetic patient with Clostridium septicum]

Atraumatic infections due to Clostridium septicum are known to be associated with immunosuppression or even malignancy. In this case report, we present a patient with severe Clostridium septicum infection related to advanced colon cancer that had not previously been diagnosed. The case demonstrates the strong association between Clostridium septicum infections and malignancy, particularly in the presence of other predisposing diseases such as diabetes mellitus. It strongly suggests excluding malignant neoplasms, especially of the gastrointestinal tract, when severe Clostridium septicum infections occur. Moreover, if patients with known colorectal or other malignancy develop septicaemia or spontaneous gas gangrene, clinicians should be aware of Clostridium septicum as one of the main causative agents, as early diagnosis and aggressive treatment are important to improve prognosis.

Epilepsy induced by extended amygdala-kindling in rats: lack of clear association between development of spontaneous seizures and neuronal damage

Most patients with temporal lobe epilepsy (TLE), the most common type of epilepsy, show pronounced loss of neurons in limbic brain regions, including the hippocampus, amygdala, and parahippocampal regions. Hippocampal damage in patients with TLE is characterized by extensive neuronal loss in the CA3 and CA1 sectors and the hilus of the dentate gyrus. There is a long and ongoing debate on whether this type of hippocampal damage, referred to as hippocampal sclerosis, is the cause or consequence of TLE. Furthermore, hippocampal damage may contribute to the progressive features of TLE. The present study was designed to determine whether development of spontaneous recurrent seizures (SRS) after extended kindling of the amygdala in rats is associated with neuronal damage. The kindling model of TLE was chosen because previous studies have shown that only part of the rats develop SRS after extended kindling, thus allowing to compare the brain pathology of rats that received the same number of amygdala stimulation but did or did not develop SRS. For extended kindling, rats were stimulated twice daily 3-5 days a week for up to about 280 stimulations. During long-term EEG/video monitoring, SRS were observed in 50% of the rats over the period of extended kindling. SRS often started with myoclonic jerks or focal seizures and subsequently progressed into secondarily generalized seizures, so that the development of SRS recapitulated the earlier kindling of elicited seizures. No obvious neurodegeneration was observed in the CA1 and CA3 sectors of the hippocampus, the amygdala, parahippocampal regions or thalamus. A significant bilateral reduction in neuronal density was determined in the dentate hilus after extended kindling, but this reduction in hilar cell density did not significantly differ between rats with and without observed SRS. Determination of the total number of hilar neurons and of hilar volume indicated that the reduced neuronal density in the dentate hilus was due to expansion of hilar area but not to neuronal damage. The data demonstrate that extended kindling does not cause any hippocampal damage resembling hippocampal sclerosis, but that SRS develop in the absence of such damage.

[Surgical site infections in hospitals and outpatient settings. Results of the German nosocomial infection surveillance system (KISS)]

About 1,000,000 hospital days attributable to surgical site infections can be expected per year in German hospitals. Among the various measures for prevention, surveillance of surgical site infections is strongly recommended. Therefore, beginning in 1997 the National Reference Center for Surveillance of Nosocomial Infections began to establish a hospital infection surveillance system in order to provide data for prevention and control of these infections. The surveillance system (called KISS) documents postoperative surgical site infections in patients undergoing selected indicator procedures. Today we have an overview of 274,050 procedures for a total of 20 operative indicator procedures. A further surveillance component focussing on surgical site infections in outpatient settings has recently been developed (AMBU-KISS). The participating hospitals and outpatient settings regularly receive their infection rates as well as the equivalent data of all hospitals involved in order to assess the position of their own hospital. However, competent and meaningful interpretation of these data is necessary for internal quality management in order to avoid wrong conclusions. The available results demonstrate that this approach can lead to a substantial reduction of surgical site infections.

Die Norovirus-Epidemie in Berlin - Klinik, Epidemiologie und Prävention

INTRODUCTION

During the winter 2002/2003, an increased number of outbreaks of acute gastroenteritis caused by norovirus was reported from Germany, some other European countries and the USA. In this study, the epidemiological and clinical features of the Berlin norovirus outbreak were investigated in order to identify the reasons for the spread of norovirus gastroenteritis and possible control measures.

METHODS

Cases and spread of norovirus infection in eleven long-term care facilities and a university hospital in Berlin were monitored from October 2002 to February 2003. To investigate the symptomatology and routes of transmission, a retrospective and interview-based study of infected staff members was performed.

RESULTS

Norovirus outbreaks in eleven long-term care facilities affected 314 patients (attack rate: 28.3 %, rate of hospitalisation: 20.7 %). 219 persons were affected in the hospital, during a period of four months. Sequence analysis revealed the circulation of Norovirus genogroup II (Grimsby-like viruses). The mean duration of symptoms was 69 hours. The duration of outbreaks on specific wards was negatively correlated with the time of returning to work (mean: 1.8 days) of the staff members after the disease.

DISCUSSION

This report demonstrates the potential of norovirus to cause large outbreaks by person to person transmission. Spread by aerosols generated by vomiting and environmental contamination seem to be particular important in institutional settings. The duration of symptoms was longer than reported previously, reflecting a possible increased virulence. Besides this, the outbreak was facilitated by insufficient preventive measures.

N-methyl-D-aspartate receptor blockade after status epilepticus protects against limbic brain damage but not against epilepsy in the kainate model of temporal lobe epilepsy

Most patients with temporal lobe epilepsy (TLE), the most common type of epilepsy, show pronounced loss of neurons in limbic brain regions, including the hippocampus. The massive neurodegeneration in the hippocampus is known as hippocampal sclerosis, and is considered one of the hallmarks of this type of difficult-to-treat epilepsy. There is a long and ongoing debate on whether this sclerosis is the result of an initial pathological event, such as a status epilepticus (S.E.), stroke or head trauma, which often precedes the development of TLE, or is caused by the spontaneous recurrent seizures (SRS) once epilepsy has developed. At present, pharmacological prevention of limbic sclerosis is not available. In a clinical situation, such prevention would only be possible if delayed cell death developing after an initial pathological event is involved. Assuming that sclerotic brain lesions provoke epileptogenesis and that delayed cell death is involved in these lesions, it should be possible to prevent both the lesions and the epilepsy by a prophylactic treatment after an initial insult such as an S.E. In order to test this hypothesis, we used a rat model of TLE in which limbic brain lesions and epilepsy with SRS develop after a kainate-induced S.E. A single low dose of the N-methyl-D-aspartate (NMDA) receptor blocker dizocilpine (MK-801) significantly reduced the damage in limbic regions, including the hippocampus and piriform cortex, and completely protected several rats from such damage when given after an S.E. of 90 min induced by kainate, strongly suggesting that delayed cell death is involved in the damage. This was substantiated by the use of molecular and immunohistochemical markers of delayed active ("programmed") cell death. However, the neuroprotection by dizocilpine did not prevent the development of SRS after the S.E., suggesting that structures not protected by dizocilpine may play a role in the genesis of SRS or that epileptogenesis is not the consequence of structural lesions in the limbic system. The only brain regions that exhibited neuronal damage in all rats with SRS were the hilus of the dentate gyrus and the mediodorsal thalamus, although treatment with dizocilpine reduced the severity of damage in the latter region. The data indicate that NMDA receptor blockade immediately after a prolonged S.E. is an effective means to reduce the damage produced by a sustained S.E. in several brain regions, including the hippocampus, but show that this partial neuroprotection of the limbic system does not prevent the development of epilepsy.

Hypothermia and undressing associated with non-fatal bromazepam intoxication

A 42-year-old woman with a history of depression was found unconscious, lying near her car in an early autumn morning. The lower part of her body was undressed and there were multiple purple spots and excoriations on the body suggesting at first a sexual assault. On admission to the intensive care unit, she presented a hypothermia with a central temperature of 28.4 degrees C. The biological samples obtained at the hospital were analysed. Blood concentration of bromazepam was 7.7 mg/l, which is above the highest level reported till now in a case of fatal intoxication.

Repeated low-dose treatment of rats with pilocarpine: low mortality but high proportion of rats developing epilepsy

Systemic administration of pilocarpine in rats can result in a chronic behavioral state that is similar to human temporal lobe epilepsy. The pilocarpine model of epilepsy is widely used for studying the factors that contribute to the development of epilepsy as a consequence of status epilepticus (SE). For this purpose, pilocarpine is either administered alone at a high systemic dose or in combination with lithium, which markedly potentiates the convulsant effect of pilocarpine. Both experimental protocols, however, are associated with high mortality rates. In the present study, we evaluated whether mortality rate in rats can be decreased by repeated administration of low doses of pilocarpine. The time the rats spent in SE was limited by diazepam. Preliminary experiments in lithium-free rats indicated that repeated low-dose administration of pilocarpine is too time-consuming to produce SE compared to single high-dose administration. All subsequent experiments were performed in lithium-pretreated rats. Single-dose injection of 30 mg/kg pilocarpine produced SE in approximately 70% of the animals, but 45% of the rats died although SE was interrupted by diazepam after 90 min. Repeated i.p. administration of 10 mg/kg pilocarpine at 30-min intervals resulted in SE after 2-4 injections; the mean dose of pilocarpine needed to induce SE was 26 mg/kg. When SE was interrupted after 90 min, mortality rate was below 10%, which was significantly lower compared to the protocol with one single administration of 30 mg/kg pilocarpine. In contrast to mortality rate, the development of spontaneous recurrent seizures did not differ between experimental protocols. Almost all rats which had experienced a SE of at least 60 min developed chronic epilepsy. Average latency to the first spontaneous seizure was approximately 40 days. The frequency and severity of spontaneous seizures was not significantly different between protocols, although animal groups with repeated low-dose treatment tended to have higher frequencies of spontaneous seizures compared to single-dose administration. The present study demonstrates that systemic treatment of lithium-pretreated rats with several low doses of pilocarpine efficiently produces SE and chronic epilepsy with much lower mortality rates than single-dose pilocarpine.

Horizontal gene transfer and host specificity of beta-haemolytic streptococci: the role of a putative composite transposon containing scpB and lmb

Beta-haemolytic streptococci are important human and animal pathogens: their genetic traits that are associated with the ability to infect human hosts remain, however, unclear. The surface protein, Lmb, mediates the adherence of Streptococcus agalactiae to human laminin. For further analysis of the corresponding gene, the adjacent genomic regions were sequenced. Lmb is localized on a putative composite transposon of 16 kb and is flanked by two copies of a novel insertion sequence element (ISSag2). It harbours the genes scpB and lmb, which are 98% identical with the respective genes of Streptococcus pyogenes. Analysis of the distribution of these genes and ISSag2 among 131 streptococcal strains revealed that all of the human isolates, but only 20% (12 of 61) of the animal isolates, contained scpB and lmb or their homologues. To investigate if the putative transposon can be mobilized, an erythromycin resistance marker was incorporated into the lmb gene of S. agalactiae. Screening for mutant strains with a regained susceptibility for erythromycin identified strains with a deletion of scpB, lmb, and one copy of ISSag2. We hypothesize that a horizontal gene transfer caused the exchange of scpB and lmb and that the ability of S. pyogenes, S. agalactiae and group C and G streptococcal strains to colonize or infect human hosts is dependent on their presence.

Targeting of liver tumour in rats by selective delivery of holmium-166 loaded microspheres: a biodistribution study

Intra-arterial administration of beta-emitting particles that become trapped in the vascular bed of a tumour and remain there while delivering high doses, represents a unique approach in the treatment of both primary and metastatic liver tumours. Studies on selective internal radiation therapy of colorectal liver metastases using yttrium-90 glass microspheres have shown encouraging results. This study describes the biodistribution of 40-microm poly lactic acid microspheres loaded with radioactive holmium-166, after intra-arterial administration into the hepatic artery of rats with implanted liver tumours. Radioactivity measurements showed >95% retention of injected activity in the liver and its resident tumour. The average activity detected in other tissues was < or =0.1%ID/g, with incidental exceptions in the lungs and stomach. Very little 166Ho activity was detected in kidneys (<0.1%ID/g), thereby indicating the stability of the microspheres in vivo. Tumour targeting was very effective, with a mean tumour to liver ratio of 6. 1+/-2.9 for rats with tumour (n=15) versus 0.7+/-0.5 for control rats (n=6; P<0.001). These ratios were not significantly affected by the use of adrenaline. Histological analysis showed that five times as many large (>10) and medium-sized (4-9) clusters of microspheres were present within tumour and peritumoural tissue, compared with normal liver. Single microspheres were equally dispersed throughout the tumour, as well as normal liver parenchyma.

The Bubi population of Equatorial Guinea characterised by HUMTH01, HUMVWA31A, HUMCSF1PO, HUMTPOX, D3S1358, D8S1179, D18S51 and D19S253 STR polymorphisms

Allele frequencies for eight STR loci (HUMTH01, HUMVWA31A, HUMCSF1PO, HUMTPOX, D3S1358, D8S1179, D18S51, D19S253) have been analysed in the Bubi population of Bioko Island, Equatorial Guinea. For all loci, no deviation from Hardy-Weinberg equilibrium was found. Data obtained were compared with that of Caucasian and African populations. Significant differences were found for all systems between all the black populations compared and the Caucasoid population. Similarities were observed between the Bubi and Zimbabweans, and also with African American populations. Also, more affinities were observed between Zimbabweans and Ugandans and Ovambos than between these groups and the Bubi population. From these comparisons it is suggested that in Africa, as in other continents, there is a certain genetic heterogeneity.

A glider swing intervention for people with dementia

The soothing, repetitive movement of rocking and swinging is well known to anyone who has enjoyed a porch swing or rocking chair. Positive effects of rocking have been reported. However, investigations on its effect in people with dementia are limited. The purposes of this quasi-experimental, repeated-measures design study were to measure the effects of a glider swing on emotions, relaxation, and aggressive behaviors in a group of nursing home residents with dementia (n = 30). Data were obtained during a 5-day baseline phase, a 10-day intervention phase, and a 5-day posttreatment phase. Subjects were placed on the glider for 20 minutes each day during the intervention phase. The results of the study indicate that the glider intervention significantly improved emotions and relaxation. The most noted changes were found after 10 minutes of swinging. However, no differences were found in aggressive behaviors.

The use of water-jetting technology in prostheses revision surgery-first results of parameter studies on bone and bone cement

Water-jet cutting techniques have been used in industrial applications for many different materials. Recently these techniques have been developed into a revolutionary cutting tool for soft tissues in visceral surgery. The present study investigates the usage of this cutting technology for the revision surgery of endoprostheses. In the first part of the study, samples of bovine bone and acrylic bone cement (PMMA) were cut using an industrial jet cutting device with pure water. Below 400 bar, only PMMA was cut; above 400 bar, bone was also cut, but only pressures above 800 bar resulted in clinically useful rates of material removal (cut depth 2. 4 mm at 10 mm/min traverse speed). In the second part of the study, the effect of adding biocompatible abrasives to the water in order to reduce the required pressure was investigated, resulting in a significantly higher removal of material. At 600 bar, PMMA was cut 5. 2 mm deep with plain water and 15.2 mm deep with added abrasives. The quality of the cuts was increased by the abrasive. Though there was no clear selectivity between bone and PMMA any more, the rate of material removal at similar pressures was significantly higher for PMMA than for bone (600 bar: 1.6 mm cut depth for bone samples, 15.2 mm for PMMA). The measured cut depths with either method were not influenced by a change of the cutting direction with respect to the main direction of the osteons in the bone. However, a reduction of the jet surface angle (90 degrees to 23 degrees ) resulted for bone in a significantly lower cut depth at 600 bar (plain water: 0.62 mm vs. 0.06 mm; abrasive: 1.61 mm vs. 0.60 mm). The laboratory experiments indicate that abrasive water jets may be suitable for cutting biomaterials like bone and bone cement.

Web-based UMLS concept retrieval by automatic text scanning: a comparison of two methods

The Web is increasingly the medium of choice for multi-user application program delivery. Yet selection of an appropriate programming environment for rapid prototyping, code portability, and maintainability remain issues. We summarize our experience on the conversion of a LISP Web application, Search/SR to a new, functionally identical application, Search/SR-ASP using a relational database and active server pages (ASP) technology. Our results indicate that provision of easy access to database engines and external objects is almost essential for a development environment to be considered viable for rapid and robust application delivery. While LISP itself is a robust language, its use in Web applications may be hard to justify given that current vendor implementations do not provide such functionality. Alternative, currently available scripting environments for Web development appear to have most of LISP's advantages and few of its disadvantages.

UMLS concept indexing for production databases: a feasibility study

OBJECTIVES

To explore the feasibility of using the National Library of Medicine's Unified Medical Language System (UMLS) Metathesaurus as the basis for a computational strategy to identify concepts in medical narrative text preparatory to indexing. To quantitatively evaluate this strategy in terms of true positives, false positives (spuriously identified concepts) and false negatives (concepts missed by the identification process).

METHODS

Using the 1999 UMLS Metathesaurus, the authors processed a training set of 100 documents (50 discharge summaries, 50 surgical notes) with a concept-identification program, whose output was manually analyzed. They flagged concepts that were erroneously identified and added new concepts that were not identified by the program, recording the reason for failure in such cases. After several refinements to both their algorithm and the UMLS subset on which it operated, they deployed the program on a test set of 24 documents (12 of each kind).

RESULTS

Of 8,745 matches in the training set, 7,227 (82.6 percent ) were true positives, whereas of 1,701 matches in the test set, 1, 298 (76.3 percent) were true positives. Matches other than true positive indicated potential problems in production-mode concept indexing. Examples of causes of problems were redundant concepts in the UMLS, homonyms, acronyms, abbreviations and elisions, concepts that were missing from the UMLS, proper names, and spelling errors.

CONCLUSIONS

The error rate was too high for concept indexing to be the only production-mode means of preprocessing medical narrative. Considerable curation needs to be performed to define a UMLS subset that is suitable for concept matching.