Glycine-induced neurotoxicity in organotypic hippocampal slice cultures

The role of the neutral amino acid glycine in excitotoxic neuronal injury is unclear. Glycine coactivates glutamate N-methyl-D-aspartate (NMDA) receptors by binding to a distinct recognition site on the NR1 subunit. Purely excitatory glycine receptors composed of NR1 and NR3/NR4 NMDA receptor subunits have recently been described, raising the possibility of excitotoxic effects mediated by glycine alone. We have previously shown that exposure to high concentrations of glycine causes extensive neurotoxicity in organotypic hippocampal slice cultures by activation of NMDA receptors. In the present study, we investigated further properties of in vitro glycine-mediated toxicity. Agonists of the glycine recognition site of NMDA receptors (D-serine and D-alanine) did not have any toxic effect in hippocampal cultures, whereas competitive blockade of the glycine site by 7-chlorokynurenic acid was neuroprotective. Stimulation (taurine, beta-alanine) or inhibition (strychnine) of the inhibitory strychnine-sensitive glycine receptors did not produce any neurotoxicity. The toxic effects of high-dose glycine were comparable in extent to those produced by the excitatory amino acid glutamate in our model. When combined with sublethal hypoxia/hypoglycemia, the threshold of glycine toxicity was decreased to less than 1 mM, which corresponds to the range of concentrations of excitatory amino acids measured during in vivo cerebral ischemia. Taken together, these results further support the assumption of an active role of glycine in excitotoxic neuronal injury.

Antimicrobial susceptibility to levofloxacin and other antibacterial agents among common respiratory pathogens—a Brazilian perspective from the GLOBAL Surveillance Initiative 2001–2002

The GLOBAL (Global Landscape On Bactericidal Activity of Levofloxacin) Surveillance programme monitored antimicrobial susceptibility patterns of the key respiratory tract pathogens Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected in Brazil during 1997-1998, 1999-2000 and 2001-2002. Penicillin and azithromycin resistance among S. pneumoniae strains increased from 1997-1998, reaching 7.9% and 9.5%, respectively, in 2001-2002. Although decreasing by 4.9% since the previous study, trimethoprim-sulphamethoxazole resistance remained high at 33.7%. Concurrent resistance to penicillin, azithromycin and trimethoprim-sulphamethoxazole was seen in 2.9% of the S. pneumoniae isolates collected. Levofloxacin remained extremely active against S. pneumoniae, with 0.3% resistance reported in 1997-1998 and 0% resistance in 1999-2000 and 2001-2002. beta-Lactamase production in H. influenzae was > 10% in all three studies, with correspondingly high rates of ampicillin resistance. Trimethoprim-sulphamethoxazole was the least active agent tested against H. influenzae, with resistance rates of > 40% recorded in all three studies. All H. influenzae isolates were susceptible to cefuroxime, ceftriaxone, azithromycin and levofloxacin. Of the M. catarrhalis isolates, 98.0% in 1997-1998, 98.0% in 1999-2000 and 81.8% in 2001-2002 were beta-lactamase-positive. The continued high prevalence of antimicrobial resistance in Brazil underscores the importance of current surveillance initiatives. Levofloxacin, a fluoroquinolone prescribed widely for respiratory tract infections, continued to show potent activity against key respiratory pathogens.

Die Karotisstenose: Diagnostik, Patientenselektion, Therapie

Atheromatöse Verengungen der Arteria carotis interna im Bereich der Bifurkation sind mit einem Hirnschlagrisiko verbunden, das 20–25% nach drei Jahren für hochgradige symptomatische Stenosen und 2–3% pro Jahr für hochgradige asymptomatische Stenosen beträgt. Die Diagnose einer Karotisstenose wird entweder nach einem zerebralen ischämischen Ereignis oder anlässlich einer Gefäßuntersuchung gestellt, wobei die Doppler/Duplex-Sonographie als Screening-Methode der Wahl eingesetzt wird. Die Ultrasonographie ermöglicht auch eine präzise Bestimmung des Stenosegrades und demzufolge des Hirnschlagrisikos. Die Bestätigung des sonographischen Befundes wird heutzutage mit Hilfe der MR- oder CT-Angiographie nicht-invasiv durchgeführt. Steht die Diagnose einer Karotisstenose fest, wird die Frage nach ihrer Behandlung individuell entschieden, wobei eine operative Behebung der Stenose zusätzlich zur besten medizinischen Therapie nur einen Sinn hat, wenn die Risiken des Eingriffes signifikant kleiner sind als die Risiken der medizinischen Therapie allein. Für die Einschätzung der perioperativen Risiken werden nur die Mortalität und die schwere neurologische Morbidität berücksichtigt. Die lokalen und systematischen Komplikationen sind vorübergehender Natur und beeinflussen das Endresultat der Intervention nicht. Eine hochgradige symptomatische Karotisstenose (70–99%) wird, wenn immer möglich, operativ behandelt. Eine mittelgradige symptomatische Stenose (50–69%) wird operiert, wenn sie mit einem hohen Hirnschlagrisiko verbunden ist. Eine hochgradige asymptomatische Stenose wird nur operiert, wenn die geschätzte perioperative Komplikationsrate weniger als 3% beträgt. Eine mittelgradige asymptomatische Stenose, sowie leichtgradige Stenosen werden nicht operiert, sondern nur medizinisch behandelt. Die Karotisendarterektomie gilt aktuell als Methode der Wahl für die operative Behandlung einer Karotisstenose, wobei eine Rate schwerer Komplikationen von weniger als 1% in erfahrenen Zentren erreicht wird. Der Vorteil der Operation hält sich über Jahre und die Restenoserate ist sehr tief. Als Alternative zur offenen Operation wird die endovaskuläre Therapie mit Angioplastie und Stenteinlage zunehmend angewandt. Aktuell fehlt noch die Evidenz für den primären Einsatz dieser Methode. Technische Fortschritte werden voraussichtlich die Sicherheit und Wirksamkeit der endovaskulären Therapie in der Zukunft entscheidend steigern.

Influence of ethinyloestradiol propanolsulphonate on serum bile acids in healthy volunteers

The present work was done to clarify the relevance of altered serum bile acid (BA) profile in healthy women after the administration of the depot oestrogen ethinyloestradiol propanolsulphonate (EES). In the serum of 20 healthy women before and two times after oral EES application, 11 free and 14 taurine- and glycine-conjugated BA were analysed by HPLC with postcolumn derivatisation and fluorescence detection. EES significantly enhanced the total serum BA concentration and that of taurine-conjugated BAs, more pronounced the secondary BAs taurodeoxycholic, tauroursodeoxycholic and taurolithocholic acid. These secondary BAs are produced in the intestine by bacteria due to 7alpha-dehydroxylation of the primary BAs cholic and chenodeoxycholic acid. Because of unchanged free BAs, also produced by intestinal bacteria due to deconjugation, the results were interpreted as a sign of disturbed transport of BAs into the liver. Inhibition of the liver Na(+)-bile salt co-transporter (Ntcp) in the sinusoidal membrane by ethinyloestradiol, formed from the prodrug EES, may be responsible for the altered BA profile in serum.

Effects of cerebral perfusion pressure and increased fraction of inspired oxygen on brain tissue oxygen, lactate and glucose in patients with severe head injury

OBJECTIVE

The purpose of the study was to measure the effects of increased inspired oxygen on patients suffering severe head injury and consequent influences on the correlations between CPP and brain tissue oxygen (PtiO2) and the effects on brain microdialysate glucose and lactate.

METHODS

In a prospective, observational study 20 patients suffering severe head injury (GCS< or =8) were studied between January 2000 and December 2001. Each patient received an intraparenchymal ICP device and an oxygen sensor and, in 17 patients brain microdialysis was performed at the cortical-subcortical junction. A 6 h 100% oxygen challenge (F IO2 1.0) ( Period A) was performed as early as possible in the first 24 hours after injury and compared with a similar 6 hour period following the challenge ( Period B). Statistics were performed using the linear correlation analysis, one sample t-test, as well as the Lorentzian peak correlation analysis.

RESULTS

F IO2 was positively correlated with PtiO2 (p < 0.0001) over the whole study period. PtiO2 was significantly higher (p < 0.001) during Period A compared to Period B. CPP was positively correlated with PtiO2 (p < 0.001) during the whole study. PtiO2 peaked at a CPP value of 78 mmHg performing a Lorentzian peak correlation analysis of all patients over the whole study. During Period A the brain microdialysate lactate was significantly lower (p = 0.015) compared with Period B. However the brain microdialysate glucose remained unchanged.

CONCLUSION

PtiO2 is significantly positively correlated with F IO2, meaning that PtiO2 can be improved by the simple manipulation of increasing F IO2 and ABGAO2. PtiO2 is positively correlated with CPP, peaking at a CPP value of 78 mmHg. Brain microdialysate lactate can be lowered by increasing PtiO2 values, as observed during the oxygen challenge, whereas microdialysate glucose is unchanged during this procedure. Extension of the oxygen challenge time and measurement of the intermediate energy metabolite pyruvate may clarify the metabolic effects of the intervention. Prospective comparative studies, including analysis of outcome on a larger multicenter basis, are necessary to assess the long term clinical benefits of this procedure.

Diagnostic management of orthostatic intolerance in the workplace

OBJECTIVE

Orthostatic intolerance (OI) is a syndrome that is characterised by headache, concentration difficulties, palpitation of the heart, dizziness associated with postural tachycardia and plasma norepinephrine concentrations that are disproportionately high when the sufferer is in the upright posture. In contrast to other forms of orthostatic dysregulation - orthostatic hypotension (OH) and postural orthostatic tachycardia syndrome (POTS) - OI, hitherto, could be diagnosed only by a tilt table examination, with high expenditure. In this paper we examine the reliability and validity of a questionnaire as a screening instrument for OI.

METHODS

We studied 138 young men (mean age 21.6 years) who were undergoing military service. After a medical check and filling in the questionnaire, the participants underwent a tilt table test including monitoring of blood pressure, heart rate and plasma catecholamines, in the supine position and during 30 min of standing. The questionnaire consisted of ten items registering presence and frequency of typical OI symptoms.

RESULTS

Probands (104) showed normal tilt table test results. OI was diagnosed in 14 probands, OH in 6 and POTS in 14. The OI participants scored significantly higher in the questionnaire than the healthy subjects did: the mean score of the OI group was 22.6, the healthy participants had a mean score of 3.9. Participants with POTS had a mean score of 13.5 and subjects with OH had a mean score of 17.0. Reliability analysis showed a Cronbach's alpha of 0.888. Validity analysis showed that 93.5% of the probands with any kind of orthostatic dysregulation can be detected.

CONCLUSIONS

We were able to establish a short questionnaire as a reliable and valid screening instrument for OI. Usage of this questionnaire can simplify enormously the diagnostic management of patients with suspected OI.

In vitro investigation of a standardized dried extract of Citrullus colocynthis on liver toxicity in adult rats

A standardized extract of Citrullus colocynthis used as an oral natural laxative in folk medicine was tested for its influence on liver function parameters in vitro. Cytochrome P450 (CYP) dependent production of reactive oxygen species (ROS) under the influence of Citrullus colocynthis extract was investigated by means of stimulated lipid peroxidation (LPO), H2O2 formation and amplified chemiluminescence in rat liver microsomes. In rat liver 9000 x g supernatants 4 monooxygenase reactions mediated by different CYP forms were measured. Putative hepatotoxic effects of Citrullus colocynthis extract were measured by means of potassium and GSH concentrations in and LDH leakage from precision-cut rat liver slices. For possible hepatoprotective effects the influence of the extract on carbon tetrachloride-induced changes of these parameters was investigated. Citrullus colocynthis extract in concentrations higher than 10 microg/ml incubation mixture proved to inhibit lipid peroxidation and ROS-production as well as CYP1A-, 2B- and 3A-dependent reactions with typical substrates. In contrast, H2O2 production was not reduced under the influence of the extract, a slight but significant increase was seen. Citrullus colocynthis extract was found to be free of hepatotoxic effects in concentrations up to 100 microg/ml incubation mixture when liver slices were incubated in William's medium E for 22 hours. All viability parameters used were not influenced by the extract of Citrullus colocynthis. Carbon tetrachloride induced hepatotoxicity could not be prevented or alleviated. Moreover, the damage was sometimes enhanced by higher extract concentrations.

Health consequences of an intravenous injection of metallic mercury

BACKGROUND

Mercury poisoning presents a variety of clinical pictures depending on chemical structure, the route of exposure, amount absorbed and individual factors. Thus, an injection of metallic mercury can be considered relatively harmless in contrast to inhalation of mercury vapor. Injection of elemental mercury is rare, and a total of only 78 cases have been reported in the literature over the period 1923-2000.

CASE REPORT

We report a suicide attempt by intravenous injection of approximately 8 g metallic mercury. By X-ray examination widespread multiple mercury shadows were visible in the whole lung and also in the subcutaneous region of the cubital fossa, the small pelvis and the right hypogastrium. Mercury excretion after treatment with 2,3-dimercaptopropane-1-sulfonate (DMPS) was significantly higher than in occupationally exposed workers.

CLINICAL SYMPTOMS

The patient showed symptoms typical of acute mercury intoxication, including gastroenteritis, ulceromembranous colitis and stomatitis mercuralis. No biochemical abnormalities in hepatic or renal function occurred, despite the persistence of metallic densities in the body. The patient's lung function was normal. The patient transitionally developed erethismus and tremor mercuralis. After 1 month of DMPS treatment, the mercury levels in blood were still high and the tremor was persistent. Three years after the suicide attempt the surgical removal of residual mercury in the left fossa cubitalis was performed. The extirpation of residual mercury was successful in cutting the mercury levels to almost half. After the operation the patient showed no symptoms of chronic mercury intoxication.

CONCLUSIONS

Since only 1 mg of mercury per day could be removed with DMPS treatment, it can be calculated, that it would take about 8,000 daily treatments to remove a total of 8 g solely by DMPS. Although DMPS itself does not dissolve the metallic deposits, it may considerably reduce the blood level of mercury and may therefore mitigate clinical symptoms, albeit transitorily. We therefore recommend that in cases of symptomatic metallic mercury injections, where the mercury cannot be removed by surgery, the patient's condition should be managed by repeated long-term DMPS treatment in order to control blood mercury levels.

Magnetic resonance angiography with ultrashort echo times reduces the artefact of aneurysm clips

We evaluated the ability of an ultrashort echo time (TE) three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequence to reduce the metal artefact of intracranial aneurysm clips and to display adjacent cerebral arteries. In five patients (aged 8-72 years) treated with Elgiloy or Phynox aneurysm clips we prospectively performed a conventional (TE 6.0 ms) and a new ultrashort TE (TE 2.4 ms) 3D TOF MRA. We compared the diameter of the clip-induced susceptibility artefact and the detectability of flow in adjacent vessels. The mean artefact diameter was 22.3+/-6.4 mm (range 14-38 mm) with the ultrashort TE and 27.7+/-6.4 mm (range 19-45 mm) with the conventional MRA ( P<0.0001). This corresponded to a diameter reduction of 19.5+/-9.2%. More parts of adjacent vessels were detected, but with less intense flow signal. The aneurysm dome and neck remained within the area of signal loss and were therefore not displayed. Ultrashort TE MRA is a noninvasive and fast method for improving detection of vessels adjacent to clipped intracranial aneurysms, by reducing clip-induced susceptibility artefact. The method cannot, however, be used to show remnants of the aneurysm neck or sac as a result of imperfect clipping.

Estrogen sulfamates: a new approach to oral estrogen therapy

Sulfamate substitution (-O-SO2-NH2) at carbon atom 3 of the steroid skeleton leads to orally active prodrugs of estrogens with much higher systemic, but lower hepatic, estrogenic activity than their parent steroids. This dissociation is achieved by first passage through the liver in erythrocytes, followed by systemic hydrolysis which releases the 'parent' estrogen. In the rat, orally administered tritiated estradiol sulfamate, unlike estradiol, appears in the circulation at high concentrations. At Cmax, approximately one third of the administered dose forms a depot in the circulation (98% in erythrocytes, 2% in plasma). Significant estradiol, estrone and estrone sulfate concentrations were recorded in plasma during depletion of the red blood cell pool. Estradiol sulfamate (J995) has no estrogen receptor affinity per se or estrogenic activity in vitro ( i.e. without hydrolysis). Its oral uterotropic activity in rats is approximately 100 times greater than that of estradiol, however, its hepatotropic activity is only marginally elevated. These functions include bile secretion, the secretion of angiotensinogen, lipoproteins (total and high-density lipoprotein cholesterol) and insulin-like growth factor I (IGF-I). Orally administred estradiol sulfamate led to systemic estrogenic effects without significant hepatic responses, whereas estradiol and other 'conventional' estrogens exerted parallel systemic and hepatic estrogenic effects. Sulfamate technology represents an approach to the use of natural estrogens for fertility control and hormone replacement therapy in both genders. In this context, reduced effects on hemostatic factors, angiotensinogen, bile and IGF-I secretion seem the most important aspects. In addition, blood concentrations of estrogens are less variable than with conventional estrogens.

Neurobehavioral effects of vanadium

It was our aim to study whether chronic exposure to vanadium reduces cognitive abilities. We investigated effects on attention, visuospatial and visuomotor functioning, reaction time, short-term memory, and prefrontal functioning. Forty-nine vanadium exposed subjects with a mean vanadium level in urine (VanU) of 14.4 micro/L and 49 controls (VanU: 0.8 microg/L) with the same socioeconomic background were investigated. Neuropsychological tests were done using a modified Wisconsin Card Sorting Test (WCST), Block Design Test (BDT), Visual Recognition Test (VRT), Simple Reaction Time (SRT), Choice Reaction (CR), Digit Symbol Substitution (DSS), and Digit Span (DS). Exposure was assessed by using the vanadium level in urine and serum. While there were significant differences in BDT and DSS, no differences were found in WCST, SRT, CR, and DS. Significant correlations existed between the vanadium levels in urine and serum and the cognitive deficits. Vanadium concentrations around 14.2 microg/L in urine reduce neurobehavioral abilities, particularly visuospatial abilities and attention.

Follow-up of perfusion defects in pulmonary perfusion scanning after pulmonary embolism: are we too careless?

Persisting perfusion defects may still be found in pulmonary perfusion scintigraphy months or years after pulmonary embolism. The aim of this study was to investigate the rate of persisting perfusion defects and the pattern of scintigraphic follow-up of patients after pulmonary embolism. Only those patients were included into our study who received pulmonary perfusion scintigraphy between 1991 and 1999, and who had perfusion defects including at least one whole segment. These perfusion defects were considered as persisting perfusion defects if unchanged over at least 1 year. From 3640 patients examined, 451 (12.4%) had perfusion defects meeting the criteria of this study. Of those, 129 (28.6%) received a scintigraphic follow-up. In 62 patients (48.1%), a reperfusion of the defects was found. In 38 patients (29.5%), the defects persisted within a follow-up period of up to 12 weeks. However, no pulmonary perfusion scintigraphy was performed thereafter. Out of the 129 patients receiving a scintigraphic follow-up, only 29 (22.5%) had a follow-up over more than 1 year, 19 of those had persisting perfusion defects. It is concluded that our data show an inadequate scintigraphic follow-up of patients with pulmonary embolism which may lead to unnecessary anticoagulant treatment if persisting perfusion defects are misinterpreted as fresh pulmonary embolism. In many cases, there was no further follow-up even if reperfusion of the defects was lacking in early follow-up.

Antimicrobial resistance in respiratory pathogens isolated in Brazil during 1999-2000

The in vitro antimicrobial susceptibility of the respiratory pathogens Streptococcus Pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis to commonly tested and prescribed agents was investigated during 1999-2000 and compared with results obtained during a previous 1997-1998 study. Of 448 isolates of S. Pneumoniae collected and tested in 1999-2000, 77.2% were susceptible, 19.9% were intermediate, and 2.9% were resistant to penicillin, demonstrating that there were no major changes in susceptibility to penicillin from 1997-1998 (77.1% susceptible, 18.7% intermediate, 4.2% resistant). All S. Pneumoniae isolates from 1999-2000 were susceptible to levofloxacin and vancomycin and >90% were susceptible to the B-lactams (amoxicillin-clavulanate, ceftriaxone, and cefuroxime) and macrolides (axithyromycin and clarithromycin), showing that susceptibility to these agents also remained unchanged since 1997-1998. The most notable increase in resistance between the two studies was demonstrated by trimethoprim-sulfamethoxazole, which increased from 23.4% to 38.6%. Penicillin resistance correlated with resistance to B-lactams, macrolides, and trimethoprim-sulfamethoxazole in both studies. In H. influenzae, the prevalence of B-lactamase-producing isolates remained unchanged (10.6% in 1999-2000; 11.0% in 1997-1998). All H. influenzae isolates were susceptible to levofloxacine, ceftriaxone, cefuroxime, and azithromycin, and showed no change between the two studies. Trimethoprim-sulfamethoxazole resistance was present in 40.1% of isolates in 1999-2000, and in 45.2% in 1997-1998. In M. catarrhalis, the prevalence of B-lactamase-producing isolates was unchanged (97.9% in 1999-2000;98.0% in 1997-1998). The most active agents against M. catarrhalis were azithromycin (MIC(90),< or = 0.03 microg/ml) and levofloxacin (MIC(90),< or = 0.03 microg/ml). Overall, these results suggest that, in Brazil, between 1999-2000 and 1997-1998, there have been no significant changes in the susceptibility of respiratory pathogens to any of the commonly tested and prescribed agents with the exception of trimethoprim-sulfamethoxazole for S. Pneumoniae.

[Development of a proverb test for assessment of concrete thinking problems in schizophrenic patients]

Concretism is considered an important aspect of schizophrenic thought disorder. Traditionally it is measured using the method of proverb interpretation, in which metaphoric proverbs are presented with the request that the subject tell its meaning. Interpretations are recorded and scored on concretistic tendencies. However, this method has two problems: its reliability is doubtful and it is rather complicated to perform. In this paper, a new version of a multiple choice proverb test is presented which can solve these problems in a reliable and economic manner. Using the new test, it is has been shown that schizophrenic patients have greater deficits in proverb interpretation than depressive patients.

Analysis of a putative voltage-gated prokaryotic potassium channel

Most of the completely sequenced prokaryotic genomes contain genes of potassium channel homologues, but there is still not much known about the role of these proteins in prokaryotes. Here we describe the large-scale overproduction and purification of a prokaryotic voltage-gated potassium channel homologue, Kch, from Escherichia coli. After successful overproduction of the protein, a specific increase in the potassium permeability of the cells was found. Kch could be purified in large amounts using classical purification methods to prevent aggregation of the protein. The physiological state of the protein was revealed to be a homotetramer and the protein was shown to be localized to the cytoplasmic membrane of the cells. In the course of the localization studies, we found a specific increase in the density of the cytoplasmic membrane on Kch production. This was linked to the observed increase in the protein to lipid ratio in the membranes. Another observed change in the membrane composition was an increase in the cardiolipin to phosphatidylglycerol ratio, which may indicate a specific cardiolipin requirement of Kch. On the basis of some of our results, we discuss a function for Kch in the maintenance of the membrane potential in E. coli.

Fertilizing characteristics of bovine sperm with flattened or indented acrosomes

Frozen semen from a control bull (C: 89% morphologically normal sperm) and two bulls with acrosomal defects (K1: 92% flattened acrosomes; K2: 82% indented acrosomes) were used to investigate the fertilizing ability of bull sperm with flattened or indented acrosomes. In experiment 1, frozen-thawed sperm were evaluated for acrosomal integrity with fluorescent microscopy. In experiment 2, proteolytic activity of the acrosomal contents of sperm was evaluated through a gelatin digestion assay. In experiment 3, an IVF test system was used to determine the ability of sperm with flattened or indented acrosomes to bind to bovine oocytes and penetrate the zona pellucida. In experiment 4, IVM zona-free bovine oocytes (ZFO) were fertilized and examined to evaluate sperm chromatin decondensation. In experiment 1, bulls K1 and K2 had a lower proportion of sperm with intact acrosomes (0 and 13.6 +/- 4.5%, respectively) than bull C (30.2 +/- 5.6%) after 2h of incubation. In experiment 2, the proportion of sperm with proteolytic activity, as indicated by gelatin digestion around sperm heads, did not differ among bulls (C: 55%, n=410; K1: 43%, n=426; K2: 48%, n=324). In experiment 3, a lower proportion of sperm with flattened (K1) or indented acrosomes (K2) bound to oocytes than sperm from the control bull, C. The percentage of zona penetrated (55%, n=20; 13%, n=23; 4%, n=25) and the mean (+/- S.E.M.) number of sperm penetrating these zona pellucida (19.7 +/- 2.5; 6.9 +/- 1.0; and 2.6 +/- 0.5) was higher (P<0.05) for bull C than for bulls K1 or K2, respectively. In experiment 4, the percentage of ZFO penetrated (95%, n=20; 52%, n=30; 30%, n=33) and the mean (+/- S.E.M.) number of sperm with chromatin decondensation (7.8 +/- 1.6; 0.8 +/- 0.2; and 0.3 +/- 0.1) were also higher (P<0.05) for the control bull, C than for bulls K1 or K2, respectively. Results suggest that although sperm with the flattened or indented acrosomes had a tendency to undergo spontaneous acrosome reaction on incubation after thawing, the proteolytic activity of the acrosomal contents appeared to be normal. Sperm with the flattened or indented acrosomes also appeared to have a reduced ability to fuse with oolemma as demonstrated by confocal microscopy. This would impair the ability to penetrate ooplasm and undergo sperm chromatin decondensation.

Pathogen frequency and resistance patterns in Brazilian hospitals: summary of results from three years of the SENTRY Antimicrobial Surveillance Program

BACKGROUND

Pathogen frequency and resistance patterns may vary significantly from country to country and also in different hospitals within a country. Thus, regional surveillance programs are essential to guide empirical therapy and infection control measures.

METHODS

Rank order of occurrence and antimicrobial susceptibility of pathogenic species causing bloodstream infections (BSI), lower respiratory tract infections (LRTI), wound or skin and soft tissue infections (WSSTI), and urinary tract infections (UTI) in hospitalized patients were determined by collecting consecutive isolates over a specified period of time, as part of the SENTRY Antimicrobial Resistance Surveillance Program (SENTRY). All isolates were tested by reference broth microdilution.

RESULTS AND CONCLUSIONS

A total of 3,728 bacterial strains were obtained from January, 1997, to December, 1999, from 12 Brazilian hospitals located in 4 states. The largest number of isolates were obtained from patients with BSI (2,008), followed by LRTI (822 cases), UTI (468 cases), and WSSTI (430 cases). Staphylococcus aureus was the most frequently isolated pathogen in general (22.8% - 852 isolates), followed by E. coli (13.8% - 516 cases) and Pseudomonas aeruginosa (13.3% - 496 cases). Staphylococcus aureus was also the most common species isolated from BSI (23.6%) and WSSTI (45.8%), and P. aeruginosa was the most frequent species isolated from patients with LRTI (29.4%). The main bacterial resistance problems found in this study were: imipenem resistance among P. aeruginosa (69.8% susceptibility) and Acinetobacter spp. (88.1% susceptibility); ESBL production among K. pneumoniae (48.4%) and E. coli (8.9%); resistance to third generation cephalosporins among Enterobacter spp. (68.1% susceptible to ceftazidime) and oxacillin resistance among S. aureus (34.0%) and coagulase negative staphylococci (80.1%). Only the carbapenems (88.1% to 89.3% susceptibility) showed reasonable activity against the Acinetobacter spp. isolates evaluated.

Long-term follow-up of an epidemiologically defined cohort of patients with Tourette syndrome

The goal of this study was to collect prospective longitudinal information on the development of an epidemiologically defined cohort of patients with Tourette syndrome. These data may improve prognostic understanding of the condition. This information will also be important for specification of an adult phenotype for genetic marker studies. A prospective longitudinal cohort study was conducted. Fifty-four of 73 patients from our 1986 prevalence study of Tourette syndrome in North Dakota school-aged children were eligible for inclusion. The subjects were diagnosed in 1984 and 1985. We were able to interview 39 of 54 eligible patients for 507 person-years of follow-up. For the cohort, tic severity declined by 59%, global assessment of functioning improved by 50%, and the average number of comorbidities decreased by 42%. Forty-four percent of patients were essentially symptom free at follow-up. Only 22% were on medication as adults. Tourette syndrome is a developmental neuropsychiatric disorder with a long-term course that is favorable for most patients. Males demonstrated substantially more variability in improvement but overall demonstrated more improvement than females.

Imaging tumors with peptide-based radioligands

Regulatory peptides are small, readily diffusable and potent natural substances with a wide spectrum of receptor-mediated actions in humans. High affinity receptors for these peptides are (over-) expressed in many neoplasms, and these receptors may represent, therefore, new molecular targets for cancer diagnosis and therapy. This review aims to give an overview of the peptide-based radiopharmaceuticals which are presently already commercially available or which are in advanced stages of their clinical testing so that their broader availability is anticipated soon. Physiologically, these peptides bind to and act through G protein-coupled receptors in the cell membrane. Historically, somatostatin analogs are the first class of receptor binding peptides having gained clinical application. 111In-DTPA-[D-Phe1]-octreotide is the first and only radiopeptide which has obtained regulatory approval in Europe and the United States to date. Extensive clinical studies involving several thousands of patients have shown that the major clinical application of somatostatin receptor scintigraphy is the detection and the staging of gastroenteropancreatic neuroendocrine tumors (carcinoids). In these tumors, octreotide scintigraphy is superior to any other staging method. However, its sensitivity and accuracy in other, more frequent neoplasms is limited. Radiolabeled vasoactive intestinal peptide (VIP) has been shown to visualize the majority of gastrointestinal adenocarcinomas, as well as some neuroendocrine tumors, including insulinomas (the latter being often missed by somatostatin receptor scintigraphy). Due to the outstanding diagnostic accuracy of the pentagastrin test in detecting the presence, persistence, or recurrence of medullary thyroid cancer (MTC), we postulated the expression of the corresponding (ie. cholecystokinin [CCK-] -B) receptor type in human MTC. This receptor is also widely expressed on human small-cell lung cancer. Indeed, 111In-labeled DTPA derivatives of gastrin showed excellent targeting of CCK-B receptor expressing tissues in animals and patients. A variety of further peptide-based radioligands, e.g. among many others, gastrin-releasing peptide/bombesin, neurotensin, substance-P, pan-somatostatin (somatostatin derivatives which bind to all five receptor subtypes) or glucagon-like peptide-1 (glp-1) analogs (the latter for the specific detection of insulinomas), is currently under development. Summarizing, radiolabeled regulatory peptides have opened new horizons in nuclear oncology for diagnosis (and potential internal radionuclide therapy). Future work will probably reveal a multitude of novel potentially clinically useful peptide-based radioligands.

The infrared absorption of amino acid side chains

Amino acid side chains play fundamental roles in stabilising protein structures and in catalysing enzymatic reactions. These fields are increasingly investigated by infrared spectroscopy at the molecular level. To help the interpretation of the spectra, a review of the infrared absorption of amino acid side chains in H(2)O and 2H(2)O is given. The spectral region of 2600-900cm(-1) is covered.

Clinical prevalence, antimicrobial susceptibility, and geographic resistance patterns of enterococci: results from the SENTRY Antimicrobial Surveillance Program, 1997-1999

As part of the SENTRY Antimicrobial Resistance Surveillance Program, a total of 4998 strains of enterococci isolated from 1997 to 1999 were processed. The occurrence of enterococcal infections by species and site of infection was analyzed, as were the occurrence of vancomycin-resistant enterococci (VRE) and their resistance phenotypes and genotypes. Trends in antimicrobial susceptibility to a variety of agents (including experimental compounds) were also reported. Enterococci accounted for >9% of isolates from all bloodstream infections (BSIs) in North America. Ampicillin was active against strains from Latin America and Europe but not against those from the United States and Canada. US isolates were considerably more resistant to vancomycin (17% resistant strains in 1999) than were those from patients in the rest of the world. The highest proportion of VRE was observed among BSI isolates (81.7%). Quinupristin-dalfopristin, chloramphenicol, and doxycycline were the most active agents tested against VRE. The results of this study confirm the worldwide trend in increasing occurrence of enterococci and the emerging pattern of antimicrobial resistance among such isolates.

[Chronic anemia and abdominal pain as a sequela of lead poisoning]

HISTORY AND ADMISSION FINDINGS

3 years ago, a 63-year-old man underwent laparotomia due to clinical signs of acute abdominal pain. The anemia was treated with erythrocyte concentrates. Several weeks before the current admission to our outpatient department, the patient was again hospitalized because of acute abdominal pain and anemia. The patient was then transferred to the University clinic for further medical tests.

INVESTIGATIONS

In addition to a normocytic anemia, a secondary porphyria was found. Further medical tests demonstrated lead poisoning.

DIAGNOSIS, TREATMENT AND COURSE

Initially, the cause of the lead poisoning remained unclear because the patient had reported neither an occuppational nor an environmental exposure to lead. Finally, a prescription-prepared ointment was evaluated, which the patient had applied to his feet and lips over the past 3 years.

CONCLUSION

Lead poisoning can be found outside the realm of occupational exposure; therefore, the knowledge of lead poisoning is still important.

Reaction-induced infrared difference spectroscopy for the study of protein reaction mechanisms

This paper reviews state-of-the-art reaction-induced infrared difference spectroscopy of proteins. This technique enables detailed characterization of enzyme function on the level of single bonds of proteins, cofactors, or substrates. The following methods to initiate a reaction in the infrared sample are discussed: (i) light-induced difference spectroscopy, (ii) attenuated total reflection with buffer exchange, (iii) the infrared variant of stopped and continuous flow, (iv) temperature and pressure jump, (v) photolytical release of effector substances from caged compounds, (vi) equilibrium electrochemistry, and (vii) photoreduction. Illustrating applications are given including hot topics from the fields of bioenergetics, protein folding, and molecule--protein interaction.

Cytochrome P450 (P450) isoforms expression, P450 concentration, monooxygenase activities, reactive oxygen species formation, lipid peroxidation, and glutathione content in wild catch carp and tench liver--influence of a two weeks exposure to phenobarbital

Carps, both sexes, 3 years old, weighing about 1 kg, and tenches of both sexes, 6 years old, weight about 250 g, were caught from a Thuringian lake without industrial pollution in November 1995 (fish without food uptake, water temperature at about 10 degrees C) and kept for 2 weeks in basins with clean water and addition of 0, 0.1, 1.0 or 10.0 mg/l phenobarbital-Na (PB). The concentration of PB was controlled during and at the end of the exposure period. The animals were fed pellets, but no food uptake was observed. After 24-48 h in fresh water the fish were sacrificed and the following hepatic parameters were immediately determined biochemically: monooxygenase functions: cytochrome P450 (P450) content, ethylmorphine N-demethylation (EN), ethoxycoumarin O-deethylation (ECOD), ethoxyresorufin O-deethylation (EROD), 7-benzyloxy-4-methyl-coumarin O-debenzylation (BCDB); oxidase function indicators: microsomal Fe2+/NADPH dependent hydrogen peroxide formation (H2O2), microsomal Fe2+/NADPH dependent luminol and lucigenin amplified chemiluminescence (LMCL, LCCL), microsomal Fe2+/NADPH dependent lipid peroxide formation (LPO); oxidative state: lipid peroxidation products (TBARS) and GSH and GSSG. Additionally, the expression of three P450 isoforms, 1A1, 2B and 3A, was assessed immunohistochemically in tissue samples from brain, gill, heart, spleen, liver, gut and ovary of both fish species and in kidney of tenches. PB did not influence body or liver weights, but increased liver P450 concentration in both species by 50-100%, though not significantly. Carp: PB increased both EN and EROD significantly, but not ECOD and BCDB; H2O2 and TBARS were enhanced significantly. LPO, LMCL and LCCL were not significantly influenced. Tench: PB increased all monooxygenase reactions (EN, ECOD, BCDB and EROD), though only significantly ECOD; H2O2 was elevated only after treatment with 0.1 mg/l PB, whereas LPO was decreased (!) after treatment by all three concentrations, though significantly only after 1.0 mg/l PB. LMCL was depressed (not significantly), but LCCL increased 5fold. TBARS were significantly enhanced. P450 1A1 subtype expression was concentration dependently elevated by PB in gill and liver of both fish and in the heart and kidney of tenches, P450 2B and 3A isoforms expression was induced in brain, gill, heart, liver and gut of both fish and in the kidney of tenches. In summary, the increased activities of the monooxygenase reactions tested and the elevated expression of all three P450 isoforms investigated in certain tissues indicate an induction of the P450 families 1, 2 and 3 by PB in fish.

CT and MRI in acute hemorrhagic stroke

We report the case of a woman presenting with an acute onset of hemiplegia. MRI was performed and showed a hyperintense mass on diffusion-weighted imaging, with areas of high signal intensity on T2* imaging and T2/PD imaging. T1-weighted imaging showed a more inhomogeneous lesion with a central isointense part corresponding to the acute clot, as well as a peripheral crescent of hypointense plasma; since another mass lesion could not be acutely excluded, computed tomography was performed immediately afterwards, showing a hyperdense hematoma. The patient was taken to the neurosurgical operating theater, where she underwent decompressive craniotomy and evacuation of the hematoma.

P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP for the rapid activation of the Na(+),K(+)-ATPase

P(3)-[2-(4-hydroxyphenyl)-2-oxo]ethyl ATP (pHP-caged ATP) has been investigated for its application as a phototrigger for the rapid activation of electrogenic ion pumps. The yield of ATP after irradiation with a XeCl excimer laser (lambda = 308 nm) was determined at pH 6.0-7.5. For comparison, the photolytic yields of P(3)-[1-(2-nitrophenyl)]ethyl ATP (NPE-caged ATP) and P(3)-[1, 2-diphenyl-2-oxo]ethyl ATP (desyl-caged ATP) were also measured. It was shown that at lambda = 308 nm pHP-caged ATP is superior to the other caged ATP derivatives investigated in terms of yield of ATP after irradiation. Using time-resolved single-wavelength IR spectroscopy, we determined a lower limit of 10(6) s(-1) for the rate constant of release of ATP from pHP-caged ATP at pH 7.0. Like NPE-caged ATP, pHP-caged ATP and desyl-caged ATP bind to the Na(+), K(+)-ATPase and act as competitive inhibitors of ATPase function. Using pHP-caged ATP, we investigated the charge translocation kinetics of the Na(+),K(+)-ATPase at pH 6.2-7.4. The kinetic parameters obtained from the electrical measurements are compared to those obtained with a technique that does not require caged ATP, namely parallel stopped-flow experiments using the voltage-sensitive dye RH421. It is shown that the two techniques yield identical results, provided the inhibitory properties of the caged compound are taken into account. Our results demonstrate that under physiological (pH 7.0) and slightly basic (pH 7.5) or acidic (pH 6. 0) conditions, pHP-caged ATP is a rapid, effective, and biocompatible phototrigger for ATP-driven biological systems.

Influence of subchronic administration of oestrone-3-O-sulphamate on oestrone sulphatase activity in liver, spleen and white blood cells of ovariectomized rats

Inhibition of oestrone sulphatase followed by oestrogen removal from tumour cells may be a new form of endocrine therapy of breast cancer in women. We investigated the inhibitory effect of the subchronic administration of oestrone-3-O-sulphamate (EMATE), a steroid sulphatase inhibitor, to ovariectomized rats, to evaluate this method for testing new nonsteroidal inhibitors. EMATE in DMSO was administered both orally and subcutaneously (s.c.) for 7 days at doses of 0.5 and 2.5 mg/kg. In addition the rats were injected s.c. with 0.5 mg oestrone sulphate/kg 26 and 2 h before decapitation under ether anaesthesia. Oestrone sulphatase activity (ESA) was measured radiometrically using [3H]oestrone sulphate as substrate for desulphuration in white blood cells, liver homogenate, microsomes and spleen homogenate. ESA in liver microsomes was found to be nearly 40 times higher than in white blood cells while in spleen ESA was nearly half of that found in liver homogenates and white blood cells. ESA can be inhibited by EMATE down to 50-1.5% of control activity depending on the dose and administration route. The inhibition was in the order, liver homogenate < spleen < liver microsomes < white blood cells, and was more pronounced after s.c. administration of the inhibitor than after oral administration. Ovariectomy was found to be not necessary for oestrone sulphatase-inhibiting studies. Two sequential s.c. injections of oestrone sulphate enhanced the enzyme activities significantly in liver and white blood cells, but not in spleen. In conclusion, white blood cells and liver microsomes of intact female rats can be used for ESA-inhibiting studies. Sulphate-conjugated oestrone can induce oestrone sulphatase in vivo in liver and white blood cells thereby enhancing oestrogen supply in the peripheral organs.

Silent cerebral ischemia detected by diffusion-weighted MRI after carotid endarterectomy

BACKGROUND AND PURPOSE

Small emboli arising from a friable plaque during carotid endarterectomy (CEA) constitute an important risk of perioperative ischemic complications. To evaluate the incidence and significance of silent cerebral ischemic lesions of embolic origin after CEA, we prospectively examined a series of surgical patients with high-grade carotid stenosis by using diffusion-weighted MRI (DWI). We also tried to correlate postoperative ischemic lesions with the occurrence of sonographic cerebral embolic signals, the presence of plaque ulcerations, and the use of intraoperative shunting.

METHODS

Of a consecutive series of 53 patients undergoing elective CEA for high-grade carotid stenosis, 48 patients with unchanged postoperative neurological status were prospectively studied with DWI of the brain the day before and the day after the operation. The magnetic resonance images were analyzed by 2 neuroradiologists blinded to the clinical result of the operation. Any new hyperintense signal was interpreted as a postoperative ischemic lesion.

RESULTS

Forty-six (95.8%) of 48 patients had unchanged postoperative brain DWI. In 2 patients (4.2%), a new single asymptomatic hyperintense signal was observed on the side of the operation. Both lesions were small and presumably of embolic origin. They were not related to sonographic embolic signals, plaque ulcerations, or intraoperative shunting.

CONCLUSIONS

These results suggest that the incidence of silent ischemic brain lesions of embolic origin after CEA is low and does not correlate with the occurrence of intraoperative sonographic microemboli. They confirm that CEA is a safe procedure that carries a low risk of postoperative cerebral events.

Influence of subchronic administration of catechol estrogens on the formation of reactive oxygen species in rat liver microsomes

Metabolic pathways of estrogens are the formation of catechol estrogens (CE; 2- and 4-hydroxy-estrogens), redox cycling of CE and free radical generation, mediated through cytochrome P450 (P450) oxidase/reductase activity. In previous investigations subchronic administration of estrogens showed prooxidative and antioxidative activities in rat liver microsomes (BARTH et al. 1999). To find out whether or not catechol metabolites are responsible for prooxidative activity, we checked 2- and 4-hydroxy-estradiol (2OH-E2 and 4OH-E2) and the non-catechol metabolite 6alpha-hydroxy-estradiol (6alpha-OH-E2) for formation of reactive oxygen species in liver microsomes of 30-day-old male Wistar rats after 5 days treatment (1, 10 mg/kg b. wt. orally, once a day). The results were compared with those after treatment of the rats with estradiol (E2), estradiol valerate (E2V) and ethinylestradiol (EE2). In liver homogenates glutathione and lipid peroxides were determined, in microsomes NADPH-Fe++-stimulated lipid peroxidation (LPO), H2O2 generation and lucigenin (LUC) and luminol (LUM) amplified chemiluminescence (CL) were investigated. In liver 9000 x g supernatants monooxygenase activities were measured. The two catechol estrogens did not show any antioxidative activity, whereas 6alpha-OH-E2 significantly diminished lipid peroxides in the liver as well as LPO and LUM-CL in liver microsomes. Among estrogens, only EE2 showed antioxidative activity. Both CE inhibited ethoxycoumarin O-deethylation. Peroxidative activity as enhanced LUC-CL was found after 2OH-E2 (1 mg/kg b.wt.) and E2, but 10 times higher doses of both CE did not change LUC-CL. Microsomal H2O2 generation was enhanced by E2, E2V and both CE, not by 6alpha-OH-E2. The lower level of H2O2 enhancement caused by CE in comparison to E2 and E2V together with unchanged LUC-CL after high CE doses did not unequivocally prove the CE to be mainly responsible for the prooxidative activities of E2 and E2V in liver microsomes, at least in 30-day-old male rats. Unchanged GSH in the liver after CE administration supports this hypothesis.

[Results and role of carotid endarterectomy]

BACKGROUND

The indications for carotid endarterectomy have been defined on the basis of several large prospective randomised trials. Today this operation is widely performed as primary and secondary stroke prevention in patients with high grade carotid artery stenosis. Permanent quality control of the surgical results is mandatory to ensure optimal stroke prevention and further reduce perioperative complications.

METHODS

In this retrospective study we analyse the surgical results of 272 consecutive carotid endarterectomies performed in 260 patients with special emphasis on the prevention of intraoperative brain ischaemia. Patients were operated on in general anaesthesia and moderate hypothermia. Before clamping the arteries at the neck, a fast-acting barbiturate or propofol was administered intravenously to obtain burst suppression on the EEG. Transcranial Doppler sonography allowed continuous intraoperative monitoring of brain perfusion and detection of emboli. Intraoperative shunting was performed only when the collateral circulation was insufficient.

RESULTS

The postoperative course was uneventful in 249 endarterectomies (91.5%). The internal carotid artery was sonographically recanalised at hospital discharge and at 6-week follow-up in all 249 cases. Ischaemic cerebral complications were observed in 7 patients (2.6%): minor reversible brain ischaemia in 4 (1.5%), and major brain ischaemia with infarction in 3 (1.1%). Three patients died in the perioperative period, representing a mortality rate of 1.1% in this series. The overall combined stroke and death rate was 3.7%. The combined major stroke and death rate was 2.2%. Various non cerebral complications occurred in 13 patients (4.8%).

CONCLUSIONS

These results confirm that endarterectomy is a safe and efficient treatment for atherosclerotic carotid stenosis at the neck. Very low complication rates can be attained by non-invasive diagnostic methods combined with intraoperative monitoring of cerebral blood flow velocity. New upcoming endovascular therapies such as percutaneous angioplasty and stenting need to be compared with these current surgical results with regard not only to perioperative morbidity and mortality but also patency rate, restenosis, and intracerebral blood flow restoration.

Substrate binding and enzyme function investigated by infrared spectroscopy

Protein conformational changes triggered by molecule binding are increasingly investigated by infrared spectroscopy often using caged compounds. Several examples of molecule-protein recognition studies are given, which focus on nucleotide binding to proteins. The investigation of enzyme mechanisms is illustrated in detail using the Ca(2+)-ATPase of the sarcoplasmic reticulum membrane as an example. It is shown that infrared spectroscopy provides valuable information on general aspects of enzyme function as well as on molecular details of molecule-protein interactions and the mechanism of catalysis.

[Pseudostenocardia due to exposure to "electrosmog"]

HISTORY AND REASON FOR ADMISSION

A 44-year-old man had anginal-like complaints. He was convinced that cardiac problems had been caused by electromagnetic fields.

INVESTIGATIONS

Apart from hypertension and hyperlipidaemia there were no other significant findings. ECG, ergometry Holter-ECG were normal.

EXPERIMENT

We tried to verify with a double-blind provocation test if the patient's complaints had been caused by electromagnetic fields. The patient was exposed to an electric instrument without being aware whether it was switched on or off. He was questioned about his perception of the presence of an electric current.

CONCLUSION

The results of the test showed that there was no causal relation between the patient's angina-like-symptoms and electromagnetic fields. The phenomenon of electrosensitivity was probably caused by psychological mechanisms.

Ace/Fgf8 is required for forebrain commissure formation and patterning of the telencephalon

Fibroblast growth factors (Fgfs) form a large family of secreted signalling proteins that have a wide variety of roles during embryonic development. Within the central nervous system (CNS) Fgf8 is implicated in patterning neural tissue adjacent to the midbrain-hindbrain boundary. However, the roles of Fgfs in CNS tissue rostral to the midbrain are less clear. Here we examine the patterning of the forebrain in zebrafish embryos that lack functional Fgf8/Ace. We find that Ace is required for the development of midline structures in the forebrain. In the absence of Ace activity, midline cells fail to adopt their normal morphology and exhibit altered patterns of gene expression. This disruption to midline tissue leads to severe commissural axon pathway defects, including misprojections from the eye to ectopic ipsilateral and contralateral targets. Ace is also required for the differentiation of the basal telencephalon and several populations of putative telencephalic neurons but not for overall regional patterning of forebrain derivatives. Finally, we show that ace expression co-localises with anterior neural plate cells that have previously been shown to have forebrain patterning activity. Removal of these cells leads to a failure in induction of ace expression indicating that loss of Ace activity may contribute to the phenotypes observed when anterior neural plate cells are ablated. However, as ace mutant neural plate cells still retain at least some inductive activity, then other signals must also be produced by the anterior margin of the neural plate.

Iatrogenic Rupture of a Cerebral Aneurysm on the Feeding Artery of an Arteriovenous Malformation

We present the case of a patient with acute onset of headache who showed a flow-related acutely ruptured aneurysm on the feeding artery of an AVM in the angiogram. Rerupture of the aneurysm occurred during angiography after endovascular treatment with a Guglielmi detachable coil. The possible mechanisms leading to rupture of the aneurysm are discussed.

Fine-structure enhancement--assessment of a simple method to resolve overlapping bands in spectra

A simple mathematical procedure--fine-structure enhancement--has been assessed on its ability to resolve overlapping bands in spectra. Its advantages and limitations have been explored using synthetic and experimental spectra. Fine-structure enhancement involves smoothing the original spectrum, multiplying the smoothed spectrum with a weighting factor and subtracting this spectrum from the original spectrum. As a result, the fine-structure of the original spectrum is enhanced in the processed spectrum and bands that overlap in the original spectrum appear as distinct bands in the processed spectrum. To be resolved by fine-structure enhancement, Lorentzian lines have to be separated by more than their quarter width at half maximum, Gaussian lines by more than their half width at half maximum. A comparison of fine-structure enhancement and Fourier self-deconvolution shows that Fourier self-deconvolution has in theory a higher potential to resolve overlapping bands. However, this depends crucially on the correct choice of the parameters. In practice, when parameters commonly used are chosen for Fourier self-deconvolution, fine-structure enhancement leads to similar results. This is demonstrated at the example of the infrared absorbance spectrum of the protein papain, where the amide I band components could be resolved similarly with both methods. Thus, fine-structure enhancement seems to be a simple alternative to Fourier self-deconvolution that does not require specialised software.

Structural changes of the sarcoplasmic reticulum Ca(2+)-ATPase upon nucleotide binding studied by fourier transform infrared spectroscopy

Changes in the vibrational spectrum of the sarcoplasmic reticulum Ca(2+)-ATPase upon nucleotide binding were recorded in H(2)O and (2)H(2)O at -7 degrees C and pH 7.0. The reaction cycle was triggered by the photochemical release of nucleotides (ATP, ADP, and AMP-PNP) from a biologically inactive precursor (caged ATP, P(3)-1-(2-nitrophenyl) adenosine 5'-triphosphate, and related caged compounds). Infrared absorbance changes due to ATP release and two steps of the Ca(2+)-ATPase reaction cycle, ATP binding and phosphorylation, were followed in real time. Under the conditions used in our experiments, the rate of ATP binding was limited by the rate of ATP release (k(app) congruent with 3 s(-1) in H(2)O and k(app) congruent with 7 s(-1) in (2)H(2)O). Bands in the amide I and II regions of the infrared spectrum show that the conformation of the Ca(2+)-ATPase changes upon nucleotide binding. The observation of bands in the amide I region can be assigned to perturbations of alpha-helical and beta-sheet structures. According to similar band profiles in the nucleotide binding spectra, ATP, AMP-PNP, and ADP induce similar conformational changes. However, subtle differences between ATP and AMP-PNP are observed; these are most likely due to the protonation state of the gamma-phosphate group. Differences between the ATP and ADP binding spectra indicate the significance of the gamma-phosphate group in the interactions between the Ca(2+)-ATPase and the nucleotide. Nucleotide binding affects Asp or Glu residues, and bands characteristic of their protonated side chains are observed at 1716 cm(-1) (H(2)O) and 1706 cm(-1) ((2)H(2)O) and seem to depend on the charge of the phosphate groups. Bands at 1516 cm(-1) (H(2)O) and 1514 cm(-1) ((2)H(2)O) are tentatively assigned to a protonated Tyr residue affected by nucleotide binding. Possible changes in Arg, Trp, and Lys absorption and in the nucleoside are discussed. The spectra are compared with those of nucleotide binding to arginine kinase, creatine kinase, and H-ras P21.

Diffusion-weighted MRI for monitoring neurovascular interventions

Carotid stenting is increasingly considered as treatment for carotid artery disease. A reliable noninvasive method is desirable for assessing the safety of the procedure. Diffusion-weighted MRI (DWI) is sensitive to early brain ischaemia which becoming widely available and might therefore serve this purpose. We prospectively studied 19 patients referred for investigation of carotid artery disease by echo-planar whole-brain DWI before and within 24 h of stenting. The images obtained at a high b value were examined by two independent blinded reviewers for new high-signal areas consistent with ischaemia. We found that 15 patients had no new changes after stenting. One patient showed enlargement of a posterior watershed lesion after the procedure, which correlated with an increase in neurological deficit. Three other patients had presumed small embolic infarcts on DWI; two were asymptomatic and one had weakness at the hand that corresponded to an embolic infarct with a lesion on DWI in the hand notch. There were no false- positive or -negative results on DWI, when compared to clinical findings. DWI is thus a new method that can demonstrate neurologically silent or asymptomatic infants. It can be used to help to assess the safety and efficacy of neurovascular intervention.

Phosphoenzyme conversion of the sarcoplasmic reticulum Ca(2+)-ATPase. Molecular interpretation of infrared difference spectra

Time-resolved Fourier transform infrared difference spectra of the phosphoenzyme conversion and Ca(2+) release reaction (Ca(2)E(1)-P --> E(2)-P) of the sarcoplasmic reticulum Ca(2+)-ATPase were recorded at pH 7 and 1 degrees C in H(2)O and (2)H(2)O. In the amide I spectral region, the spectra indicate backbone conformational changes preserving conformational changes of the preceding phosphorylation step. beta-sheet or turn structures (band at 1685 cm(-1)) and alpha-helical structures (band at 1653 cm(-1)) seem to be involved. Spectra of the model compound EDTA for Ca(2+) chelation indicate the assignment of bands at 1570, 1554, 1411 and 1399 cm(-1) to Ca(2+) chelating Asp and Glu carboxylate groups partially shielded from the aqueous environment. In addition, an E(2)-P band at 1638 cm(-1) has been tentatively assigned to a carboxylate group in a special environment. A Tyr residue seems to be involved in the reaction (band at 1517 cm(-1) in H(2)O and 1515 cm(-1) in (2)H(2)O). A band at 1192 cm(-1) was shown by isotopic replacement in the gamma-phosphate of ATP to originate from the E(2)-P phosphate group. This is a clear indication that the immediate environment of the phosphoenzyme phosphate group changes in the conversion reaction, altering phosphate geometry and/or electron distribution.

Influence of oestrogens on formation of reactive oxygen species in liver microsomes of differently aged male Wistar rats

Metabolic pathways of oestrogens are the formation of catechol oestrogens (CE; 2- and 4-hydroxy-oestrogens), redox cycling of CE and free radical generation, mediated through cytochrome P450 (P450) oxidase/reductase activity. We checked the oestrogens oestradiol (E2), oestradiol valerate (E2V) and ethinyloestradiol (EE2) for formation of reactive oxygen species in vitro and ex vivo in male Wistar rats in dependence on age. In liver microsomes of 10-, 30-, 60- and 270-day-old rats the influence of E2, E2V and EE2 (10(-7)-10(-3) M) on NADPH-Fe(++)-stimulated lipid peroxidation (LPO), H2O2 generation and lucigenin (LUC) and luminol (LUM) amplified chemiluminescence (CL) was investigated. The same parameters, additionally P450 content and monooxygenase activities were measured in liver 9000 x g supernatants after subchronic administration of the oestrogens (1, 10 mg/kg b. wt. orally). The most important results are the strong inhibitory capacities of the oestrogens in vitro on LPO in the order of E2V < E2 < EE2, most pronounced in 10-, 60- and 270-day-old animals. In microsomes of 30-day-old rats with the highest control LPO the antioxidative effect of the oestrogens was lower. Whereas the H2O2 generation was not changed by E2, enhanced by E2V, but diminished by EE2 in all age groups, CL(LUC) and CL(LUM) were inhibited in the order of E2 < E2V < EE2. Also after subchronical treatment of the rats the antioxidative action of the oestrogens was evident, microsomal LPO was inhibited in the order of E2 < E2V < EE2. All oestrogens inhibited ethylmorphine N-demethylation. But enhanced H2O2 generation and increased CL(LUC) also indicate a formation of reactive oxygen species by these oestrogens. Obviously in vitro the antioxidative phenolic structure of the oestrogens dominates, whereas after in vivo administration the dose- and age-dependent biotransformation produces prooxidative in addition to antioxidative structures.

Two males with childhood disintegrative disorder: a prospective 14-year outcome study

A prospective 14-year outcome study of two children meeting DSM-IV criteria for childhood disintegrative disorder is presented. Their ages at first evaluation were 4 years 7 months and 6 years 3 months. Both are now adults and continue to have a severe pervasive developmental disorder, mental retardation, seizure disorder, and are non-verbal. Both require residential care.