Determination of catecholamines in rat heart tissue and plasma samples by liquid chromatography with electrochemical detection

Liquid chromatography with electrochemical detection is used for the determination of adrenaline, noradrenaline and dopamine in rat heart tissue, and the method has also been applied to the determination of basic levels of these compounds in blood plasma. The catecholamines are isolated from the biological sample by adsorption onto alumina and are then desorbed by elution with perchloric acid. The stability of the compounds during the different stages in the work-up process has been studied. A greatly simplified procedure for the preparation of alumina is presented. Both ion-pair reversed-phase and ion-exchange liquid chromatography have been used for the separation of the catecholamines. For plasma samples the method has been validated against radioenzymatic assay and the choice of method is discussed.

IgG Endopeptidase in Highly Sensitized Patients Undergoing Transplantation

BACKGROUND

Donor-specific antibodies create an immunologic barrier to transplantation. Current therapies to modify donor-specific antibodies are limited and ineffective in the most highly HLA-sensitized patients. The IgG-degrading enzyme derived from Streptococcus pyogenes (IdeS), an endopeptidase, cleaves human IgG into F(ab')₂ and Fc fragments inhibiting complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, which suggests that IdeS might be useful for desensitization. We report on the combined experience of two independently performed open-label, phase 1-2 trials (conducted in Sweden and the United States) that assessed the efficacy of IdeS with regard to desensitization and transplantation of a kidney from an HLA-incompatible donor.

METHODS

We administered IdeS to 25 highly HLA-sensitized patients (11 patients in Uppsala or Stockholm, Sweden, and 14 in Los Angeles) before the transplantation of a kidney from an HLA-incompatible donor. Frequent monitoring for adverse events, outcomes, donor-specific antibodies, and renal function was performed, as were renal biopsies. Immunosuppression after transplantation consisted of tacrolimus, mycophenolate mofetil, and glucocorticoids. Patients in the U.S. study also received intravenous immune globulin and rituximab after transplantation to prevent antibody rebound.

RESULTS

Recipients in the U.S. study had a significantly longer cold ischemia time (the time elapsed between procurement of the organ and transplantation), a significantly higher rate of delayed graft function, and significantly higher levels of class I donor-specific antibodies than those in the Swedish study. A total of 38 serious adverse events occurred in 15 patients (5 events were adjudicated as being possibly related to IdeS). At transplantation, total IgG and HLA antibodies were eliminated. A total of 24 of 25 patients had perfusion of allografts after transplantation. Antibody-mediated rejection occurred in 10 patients (7 patients in the U.S. study and 3 in the Swedish study) at 2 weeks to 5 months after transplantation; all these patients had a response to treatment. One graft loss, mediated by non-HLA IgM and IgA antibodies, occurred.

CONCLUSIONS

IdeS reduced or eliminated donor-specific antibodies and permitted HLA-incompatible transplantation in 24 of 25 patients. (Funded by Hansa Medical; ClinicalTrials.gov numbers, NCT02224820 , NCT02426684 , and NCT02475551 .).

Plasma noradrenaline correlates to sympathetic muscle nerve activity in normotensive man

Recordings of multiunit sympathetic activity were made in muscle branches of the peroneal nerve in 22 healthy subjects at rest in recumbent position. Nerve activity was quantitated in terms of burst incidence (number of pulse synchronous sympathetic bursts per 100 heart beats or per min). In a separate session, 4-45 months later, blood was drawn from an antecubital vein for noradrenaline analysis. Both sympathetic activity and plasma concentrations of noradrenaline varied widely between subjects and both parameters increased with age. There was a significant positive correlation between a subject's level of sympathetic activity and his plasma concentration of noradrenaline. It is suggested that overflow of transmitter from sympathetic terminals in muscles contributes significantly to plasma levels of noradrenaline at rest.

Integration of sperm sexing technology into the ART toolbox

Sex-sorting of mammalian spermatozoa has applications for genetic improvement of farm animals, in humans for the control of sex-linked disease, and in wildlife as a captive management strategy and for the re-population of endangered species. Considerable research has been undertaken worldwide on the Beltsville sperm sexing technology, the only effective method for pre-selection of sex of offspring. The combination of this method with assisted reproductive technologies has resulted in the birth of offspring in a wide range of animals, including cattle, the only livestock species in which sperm sexing is used commercially. Major improvements in the efficiency of sorting, in particular the development of high speed sorting (15 million X and Y spermatozoa per hour) have led to the production of offspring using conventional and low dose AI and the successful cryopreservation of sorted spermatozoa in cattle, sheep, horses and elk. A major limitation remains the short viable lifespan of sorted spermatozoa in the female genital tract, in most species necessitating sperm deposition deep in the uterus, and close to the expected time of ovulation, for acceptable fertility after in vivo insemination. Special deep uterine insemination technology has been employed to produce offspring in pigs and horses using low sperm doses. Considerable attention has been paid to reduction of the damage and capacitation-like changes to spermatozoa that result from flow cytometric sorting and from freezing and thawing. However, high-purity sorting of liquid-stored or frozen-thawed spermatozoa for immediate use, or re-cryopreservation for later use, does not reduce its fertilizing capacity in vitro, allowing its combination with in vitro fertilization or juvenile in vitro embryo transfer to produce blastocysts, and offspring in sheep and cattle after embryo transfer. Further research into sorting and preservation methods that incorporate strategies to prevent destabilization of sperm membranes may improve the fertilizing lifespan of flow cytometrically sorted spermatozoa. With continued improvement in sorting instrumentation and biological handling, sorting efficiency should reach a point where commercially acceptable pregnancy rates may be achieved in a number of species after conventional or deep uterine insemination.

Effect of freezing and thawing rates on the post-thaw viability of boar spermatozoa frozen in FlatPacks and Maxi-straws

The effects of different freezing and thawing rates on the post-thaw motility and membrane integrity of boar spermatozoa, processed as split samples in Maxi-straws or flat PET-plastic packages (FlatPack) were studied. A programmable freezing device was used to obtain freezing rates of either 20, 50 or 80 degrees C/min. Thawing of the samples was performed in a bath of circulating water; for 40s at 50 degrees C or 27s at 70 degrees C for Maxi-straws and 23s at 35 degrees C, 13s at 50 degrees C or 8s at 70 degrees C for the FlatPacks. Sperm motility was assessed both visually and with a computer assisted semen analysis (CASA) apparatus, while plasma membrane integrity was assessed using the fluorescent probes Calcein AM and ethidium homodimer-1. Temperature changes during freezing and thawing were monitored in both forms of packaging. Values for motile spermatozoa, sperm velocity and lateral head displacement variables were significantly (p<0.05) higher for samples frozen in FlatPacks than in Maxi-straws, with superior results at higher thawing rates. Freezing at 50 degrees C/min yielded better motility than 20 or 80 degrees C/min, although the effect was rather small. Neither freezing rate nor thawing rate had any effect on membrane integrity (p>0.05). A significant boar effect was seen for several parameters. The most striking difference in temperature courses between containers was a 4-5-fold lowering of the thawing rate, between -20 and 0 degrees C, in the center of the Maxi-straw, compared with the FlatPack. This is apparently due to the insulating effect of the thawed water in the periphery of the Maxi-straw. The improvement in sperm motility seen when using the FlatPack appears to be related to the rapid thawing throughout the sample, which decreases the risk of cell damage due to recrystallization during thawing. Since sperm motility patterns have been reported to be correlated with fertility both in vitro and in vivo it is speculated that the use of the FlatPack might improve the results when using frozen-thawed boar spermatozoa for artificial insemination.

Characterization of CMVpp65-specific CD8+ T lymphocytes using MHC tetramers in kidney transplant patients and healthy participants

BACKGROUND

Cytomegalovirus (CMV) is a ubiquitous herpesvirus that infects 50-90% of individuals in different populations. After primary infection, the virus persists latently in myeloid cells under the control of specific T-cells. Reactivation of CMV infection may cause lethal organ dysfunction and is frequently seen in immunosuppressed individuals. CD8+ cytotoxic T-cells (CTL) have a primary role in suppressing CMV reactivation, and the dominating CTL response is directed against pp65.

METHODS

MHC tetramers, that is, complexes between HLA class I (or class II) molecules and antigenic peptides conjugated to fluorochromes allow the direct visualization of antigen-specific receptor-carrying T-cells using flow cytometry. We constructed a novel MHC tetramer for identification of CMVpp65-specific CD8+ T-cells using HLA-A2 molecules folded with the immunodominant NLVPMVATV peptide.

RESULTS

The A2/pp65 tetramer specifically stained CMV-directed T-cell lines, and sorted cells showed CMV-specific cytotoxicity. High proportions (0.1-9%) of the CD8+ T-cells were A2/pp65 tetramer+ in healthy HLA-A2+ CMV carriers and in immunosuppressed kidney transplant patients with latent infection. Patients with reactivated CMV infection exhibited up to 15% A2/pp65 tetramer+ cells, which seemed to correlate with CMV load over time. A2/pp65 tetramer+ cells expressed T-cell activation markers.

CONCLUSIONS

The construction of a novel A2/pp65 MHC tetramer enabled the design of a rapid and precise flow cytometric method allowing quantitative and qualitative analysis of CMV-specific T-cells. The number of A2/pp65 tetramer binding CTLs in blood may prove to be clinically relevant in assessing the immune response to CMV.

Effects of holding time during cooling and of type of package on plasma membrane integrity, motility and in vitro oocyte penetration ability of frozen-thawed boar spermatozoa

The effect of a prolonged holding time (HT) during cooling on plasma membrane integrity (PMI), motility and in vitro oocyte penetration ability of boar spermatozoa frozen-thawed in different types of package was investigated. Boar semen was frozen in a split-sample design using 3 different HTs (3, 10 and 20 h) during cooling and three different types of freezing package: Maxi-straws, Medium-straws and FlatPacks. Assessment of PMI (SYBR-14 and propidium iodide, fluorescence microscopy) and sperm motility (visually and with CASA) was done during cooling (at 32 degrees C, 15 degrees C, 5 degrees C) and post-thaw (PT). The in vitro oocyte penetration ability of the spermatozoa was tested only PT, using a homologous in vitro penetration assay (hIVP). During cooling the HTs used had no significant (p<0.05) effect on either PMI or percentage of motile spermatozoa Post-thaw PMI was significantly higher (p<0.05) for 10 h and 20 h HT compared with 3 h, and the percentage of motile spermatozoa decreased significantly with 20 h HT as opposed to 3 h and 10 h. Regarding the freezing packages, the FlatPacks and Maxi-straws yielded significantly more PMI than did the Medium-straws (p<0.05). Post-thaw motility was significantly higher for FlatPacks than for straws, in terms of both percentage motile spermatozoa, and sperm velocity and lateral head displacement (LHD). The hIVP did not show any significant differences among the HTs, although FlatPacks yielded a significantly higher penetration rate and more spermatozoa per penetrated oocyte (p<0.05) than did the straws. Changes in motility patterns, toward a more circular motility during cooling and PT, could be noticed where individual spermatozoa showed a capacitation-like motility pattern. The changes were more obvious with 10-h and 20-h HTs than with 3-h HT.

Studies on the insulin-antagonistic effect of catecholamines in normal man. Evidence for the importance of beta 2-receptors

The insulin-antagonistic effect of adrenaline was studied in seven healthy subjects with the euglycaemic clamp technique using two insulin infusion rates (40 and 1200 mU X (m2)-1 min-1). The adrenergic receptor mediating the adrenaline effect was characterized by concomitant infusion of propranolol (beta 1 + beta 2-antagonist) or metoprolol (beta 1-antagonist). Each subject was studied four times (placebo, adrenaline, adrenaline + propranolol, adrenaline + metoprolol). Glucose turnover was measured with D(3-3H)-glucose. Similar plasma insulin levels were reached in all studies with the two insulin infusion rates (mean; placebo 51 +/- 3 and 7421 +/- 337 mU/l respectively). Glucose production was completely inhibited by the low insulin level during placebo infusion. Adrenaline antagonized this effect so that a significant glucose production was seen at the low but not at the high insulin level. Propranolol, but not metoprolol, reversed this insulin-antagonistic effect of adrenaline. Glucose utilization increased from 2.53 +/- 0.17 to 7.28 +/- 0.88 mg X kg-1 X min-1 during placebo when the insulin levels were increased from 4 +/- 0.3 to 51 +/- 3 mU/l. Increasing the insulin levels 150-fold to approximately 7500 mU/l only doubled the glucose utilization (14.68 +/- 1.14 mg X kg-1 X min-1). Adrenaline induced a pronounced inhibition of glucose utilization at both insulin levels (78% and 37% inhibition respectively). Propranolol, but not metoprolol, prevented this effect of adrenaline. Thus, physiological adrenaline levels exert a pronounced insulin-antagonistic effect which is mediated by beta 2-receptor stimulation. The inhibitory effect on glucose uptake is maintained even at high insulin levels when hepatic glucose production is completely abolished.

Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy

BACKGROUND

Despite the proven efficacy of acyclovir (ACV) therapy, herpes simplex encephalitis (HSE) continues to cause substantial morbidity and mortality. Among patients with HSE treated with ACV, the mortality rate is approximately 14%-19%. Among survivors, 45%-60% have neuropsychological sequelae at 1 year. Thus, improving therapeutic approaches to HSE remains a high priority.

METHODS

Following completion of a standard course of intravenous ACV, 87 adult patients with HSE (confirmed by positive polymerase chain reaction [PCR] for herpes simplex virus DNA in cerebrospinal fluid) were randomized to receive either valacyclovir (VACV) 2 g thrice daily (n = 40) or placebo tablets (n = 47) for 90 days (12 tablets of study medication daily). The primary endpoint was survival with no or mild neuropsychological impairment at 12 months, as measured by the Mattis Dementia Rating Scale (MDRS). Logistic regression was utilized to assess factors related to the primary endpoint.

RESULTS

The demographic characteristics of the 2 randomization groups were statistically similar with no significant differences in age, sex, or race. At 12 months, there was no significant difference in the MDRS scoring for VACV-treated vs placebo recipients, with 85.7% and 90.2%, respectively, of patients demonstrating no or mild neuropsychological impairment (P = .72). No significant study-related adverse events were encountered in either treatment group.

CONCLUSIONS

Following standard treatment with intravenous ACV for PCR-confirmed HSE, an additional 3-month course of oral VACV therapy did not provide added benefit as measured by neuropsychological testing 12 months later in a population of relatively high-functioning survivors.

CLINICAL TRIALS REGISTRATION

NCT00031486.

Muscle sympathetic activity and plasma noradrenaline in normotensive and hypertensive man

Micro-electrode recordings of muscle sympathetic activity were made in the peroneal nerve of 20 normotensive subjects and 18 patients with essential hypertension resting in the recumbent posture. The level of sympathetic activity was quantitated as bursts/100 heart beats or bursts/min. On another occasion blood was sampled from an antecubital vein and analyzed for plasma noradrenaline using radioenzymatic technique. In both groups the level of sympathetic activity increased with age and taking age into account there was no significant difference in sympathetic activity between normotensive and hypertensive subjects. There was no significant difference in plasma levels of noradrenaline between the groups. Both for normotensive and for hypertensive subjects there was a positive correlation between a subject's level of sympathetic activity and his plasma concentration of noradrenaline, and the regression lines did not differ significantly between the groups. It is suggested (a) that outflow of transmitter from sympathetic terminals in muscles contributes significantly to plasma concentrations of noradrenaline at rest both in normotensive and hypertensive subjects: (b) that neither for muscle sympathetic activity nor for plasma noradrenaline do the resting levels differ between normotensive and hypertensive subjects.

Field fertility with exported boar semen frozen in the new FlatPack container

The present study tested the field fertility of frozen-thawed (FT) Swedish boar semen packaged in flat plastic containers (FlatPacks) and exported for artificial insemination (AI) to overseas nucleus herds. Semen from 47 Swedish boars of Landrace (L), Yorkshire (Y), and Hampshire (H) breeds was frozen using a lactose-egg yolk-based extender with 3% glycerol and 10(9) spermatozoa/ml in 5 ml FlatPacks. For all breeds, FT sperm membrane intactness averaged 60%, while mean FT sperm motility ranged from 49 to 53%. A total of 308 litters resulted from 421 overseas inseminations with FT semen, with a mean farrowing rate (FR) of 73% and 10.7 mean number total piglets born. In a within-sow analysis for the purebred L and Y breedings, the FR and litter size of FT semen were compared with natural matings (NM) and on-farm AI with liquid semen (NW/AI breedings) at the same farms. Farrowing rate was 72.3 and 78.8% (P = 0.23), total piglets 11.3 and 11.6 (P = 0.44), and live piglets 10.1 and 10.2 (P = 0.77), for the FT semen and NM/AI breedings, respectively. The present results suggest that this freezing protocol and FlatPack container maintains high sperm viability post-thaw. Further the fertility levels when inseminated at overseas nucleus herds seem to be similar to those achieved with (NM/AI breedings) at the same farms. This freezing method may be a reliable alternative for the freezing/thawing of boar semen under commercial AI conditions.

Liquid chromatographic determination of the macrolide antibiotics roxithromycin and clarithromycin in plasma by automated solid-phase extraction and electrochemical detection

A liquid chromatographic method for the determination of the macrolide antibiotics, roxithromycin and clarithromycin, in plasma is described. The method is fully automated, employing on-line solid-phase extraction for sample clean-up, using the Prospekt unit. Plasma samples, mixed with internal standard, were injected onto exchangeable CN cartridges. After washing, the compounds were eluted and transferred to a C18 analytical column for separation and electrochemical detection. Clarithromycin was used as internal standard when assaying roxithromycin and vice versa. The recovery of the solid-phase extraction method was 90% and higher, and the relative standard deviation was about 3%. The limit of quantitation was 0.5 mumol/l when 25 microliters of plasma was injected. Comparison with a liquid-liquid extraction method for sample clean-up showed good agreement.

Effect of ischaemic on the adrenergic neurons of the rat heart: a fluorescence histochemical and biochemical study

Left coronary artery ligation was performed in pentobarbitone anaesthetised rats. Following 1/2 and 2 1/2 h of coronary artery occlusion or sham-operation the right and left ventricular myocardium and the interventricular septum were analysed for tissue content of catecholamines. In control rats and in rats with coronary artery ligation for various time periods (1/2, 2 1/2 and 5 h), the Hillarp-Falck fluorescence histochemical technique was used to visualise the catecholamines of the ventricular myocardium. The tissue noradrenaline content of the left ventricle was markedly reduced after 2 1/2 h of ischaemia while noradrenaline levels in the other parts of the ventricles were unaffected. The adrenergic innervation of the normal rat ventricles is described for the purpose of comparing the normal innervation picture with the appearance after ischaemia. A reduced catecholamine fluorescence was found mainly in the centre of the left ventricular free wall 30 min after coronary artery occlusion. After 2 1/2 and 5 h large areas of the ischaemic myocardium were found to be completely devoid of fluorescent terminals. The border zone between the areas of fluorescence disappearance and normally innervated myocardial tissue was generally quite sharp and occasionally terminals with a diffuse appearance were found in this zone. It is concluded that coronary artery ligation caused a time-dependent loss of noradrenaline from the adrenergic nerve terminals in the ischaemic myocardium. Catecholamine thus released may activate myocardial adrenoceptors and hence be related to increased ischaemic damage and ventricular arrhythmias.

Nervous control of the blood pressure in the Atlantic cod, Gadus morhua

Dorsal (PDA) and ventral aortic blood pressure (PVA) and heart rate (HR) were measured in conscious resting cod, Gadus morhua L., which has been allowed 24 h recovery from surgery. Plasma adrenalin and nonadrenalin concentrations in these fish were 3.4 and 2.2 nmoll-1 respectively, and thus lower than previously reported values from partially recovered cod. Twenty-four hours after treatment with the adrenergic neurone blocking agent bretylium, PDA was significantly reduced by 17% compared to sham-injected controls, although PVA and heart rate were unaltered. Subsequent alpha-adrenoceptor blockade by phentolamine produced no further fall in PDA and no changes in PVA or HR, provided a 5-h period was allowed to overcome the acute toxic side effects of phentolamine. The effectiveness of the bretylium or phentolamine blockade was confirmed by noting the absence of any vasoconstrictor response during sympathetic nerve stimulation in perfused tails from fish used in the in vivo experiments. Bretylium had no significant effect on the sensitivity of the isolated coeliac artery to adrenalin, but effectively blocked the adrenergic innervation of this artery or the vasculature of the tail. Evidence for a non-selective blockade of non-adrenergic nerves to the heart was also obtained. It is concluded that the adrenergic tonus affecting the dorsal aortic blood pressure in resting cod that have recovered for 24 h following surgery is due solely to an adrenergic nervous tone.

Early posthypoglycemic insulin resistance in man is mainly an effect of beta-adrenergic stimulation

The insulin effect following hypoglycemia was studied with the euglycemic clamp technique in seven healthy subjects. Following an initial euglycemic clamp hypoglycemia was induced and after glucose recovery a second clamp was performed. Glucose production (Ra) and utilization (Rd) were studied with [3-3H]glucose. Each subject was studied four times; during infusion of placebo, propranolol, somatostatin, and a control study where hypoglycemia was prevented. Hypoglycemia induced an insulin resistance with a lower steady state glucose infusion rate following the hypoglycemia during placebo as compared to the control study (2.5 +/- 0.5 and 4.8 +/- 1.0 mg/kg min, respectively, P less than 0.05). The insulin resistance was due to an attenuated insulin effect on both inhibition of Ra (impaired by 37%) and stimulation of Rd (impaired by 61%). The insulin-antagonistic effect was completely prevented by propranolol but only partly by somatostatin. Thus, early posthypoglycemic insulin resistance (2.5-3.5 h after hypoglycemia) is a sustained effect mainly due to beta-adrenergic stimulation.

Comparison of a duplex quantitative real-time PCR assay and the COBAS Amplicor CMV Monitor test for detection of cytomegalovirus

A duplex quantitative real-time PCR (qPCR) assay was designed to detect both the polymerase gene (pol) and the glycoprotein gene (gB) of cytomegalovirus (CMV). The detection limit of the qPCR was determined to be 1 to 3 copies/reaction and the linear measure interval was 10(3) to 10(8) copies/ml. The qPCR system was compared to the COBAS Amplicor CMV Monitor test (COBAS) by an analysis of 138 plasma samples. Both systems detected CMV in 71 cases and had negative results for 33 samples. In addition, 34 samples were positive by qPCR and negative by the COBAS assay, but in no case was the COBAS result positive and the qPCR result negative. Thus, qPCR detected 48% more positive cases than the COBAS method. For samples with > or = 10(5) copies/ml by qPCR, a saturation effect was seen in the COBAS assay and quantification required dilution. Copy numbers for pol and gB by qPCR generally agreed. However, the reproducibility of qPCR assays and the need for an international standard are discussed. Discrepant copy numbers for pol and gB by qPCR were found for samples from two patients, and sequence analysis revealed that the corresponding CMV strains were mismatched at four nucleotide positions compared with the gB fragment primer sequences. In conclusion, a duplex qPCR assay in a real-time format facilitates quantitative measurements and minimizes the risk of false-negative results.

Determination of catecholamines in urine by ion-exchange liquid chromatography with electrochemical detection

A liquid chromatographic method for the determination of free urinary concentrations of epinephrine, norepinephrine and dopamine is presented. For urine samples, pre-purified by adsorption onto alumina, ion-exchange chromatography was, in terms of selectivity, found to be superior to the more widely used reversed-phase chromatography. The column eluates were monitored with an electrochemical detector utilizing a glassy carbon working electrode. The method allows determination of the concentrations in 0.5 ml of normal urine samples with a relative standard deviation below 2%.

N-methyl-d-aspartate receptor autoimmunity affects cognitive performance in herpes simplex encephalitis

OBJECTIVES

To investigate the prevalence and temporal development of N-methyl-d-aspartate receptor (NMDAR) autoantibodies in relation to neurocognitive performance in patients with herpes simplex encephalitis (HSE).

METHODS

This prospective observational study enrolled a total of 49 HSE patients within a randomized controlled trial of valacyclovir. Cerebrospinal fluid and serum samples were drawn in the initial stage of disease, after 2 to 3 weeks and after 3 months. Anti-NMDAR IgG was detected with HEK293 cells transfected with plasmids encoding the NMDA NR1 type glutamate receptor. A batch of neurocognitive tests, including the Mattis Dementia Rating Scale (MDRS), Glasgow Coma Scale (GCS), Reaction Level Scale (RLS85), Mini-Mental State Examination (MMSE) and National Institutes of Health (NIH) stroke scale, was performed during 24 months' follow-up.

RESULTS

Anti-NMDAR IgG was detected in 12 of 49 participants. None were antibody positive in the initial stage of disease. In ten of 12 positive cases, specific antibodies were detectable only after 3 months. Notably, the development of NMDAR autoantibodies was associated with significantly impaired recovery of neurocognitive performance. After 24 months' follow-up, the median increase in MDRS total score was 1.5 vs. 10 points in antibody-positive and -negative participants (p=0.018).

CONCLUSIONS

Anti-NMDAR autoimmunity is a common complication to HSE that develops within 3 months after onset of disease. The association to impaired neurocognitive recovery could have therapeutical implications, as central nervous system autoimmunity is potentially responsive to immunotherapy.

Determination of fluvastatin enantiomers and the racemate in human blood plasma by liquid chromatography and fluorometric detection

Liquid chromatographic methods for the determination of fluvastatin, as racemate and as separated enantiomers, are described. Fluvastatin was extracted at pH 6.0 from blood plasma into methyl tert.-butyl ether. The organic phase was evaporated and the extract redissolved into either a phosphate buffer solution of pH 6.0 containing tetrabutylammonium fluoride and methanol for the racemate determination, or in a mixture of acetonitrile and water for assaying the enantiomers. The absolute recoveries were 95 and 86% for the racemate and the enantiomers, respectively, and the limit of quantitation 0.5 nmol/1 for the racemate, and 5 nmol/l for the enantiomers, when using half a millilitre of plasma sample. The samples were chromatographed on a C8 column (racemate) and on a Chiralcel OD-R column (enantiomers), and monitored using fluorescence detection. In the achiral system, post-column exposure of the eluate to UV light enhanced the sensitivity by 4 to 5 times when compared with analysis based on the native fluorescence.

Determination of apomorphine in plasma and brain tissue by ion-pair extraction and liquid chromatography

Apomorphine is extracted from plasma or tissue homogenate with ethyl acetate. After back-extraction into hydrochloric acid, the apomorphine is extracted as an ion pair with 3,5-di-tert.-butyl-2-hydroxybenzene sulphonate into a small volume of methylene chloride and the solution is injected into the chromatographic column. Apomorphine is separated on microporous silica with a mixture of aqueous perchloric acid, methanol and methylene chloride as the mobile phase. With absorbance measurement of the eluent at 254 nm the method permits the determination of 15 pmol of apomorphine in 1 ml of plasma or in a rat brain. The coefficient of variation was 4% at the 100 pmol level.

Radical reduction of cephalosporin use at a tertiary hospital after educational antibiotic intervention during an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae

OBJECTIVES

During an outbreak of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae at our hospital, we performed an educational antibiotic intervention aimed at reducing prescriptions of second- and third-generation cephalosporins and preventing increased use of fluoroquinolones and carbapenems. In this report, we describe the implementation strategy used and evaluate the intervention effect according to Cochrane recommendations.

METHODS

New recommendations for empirical intravenous antibiotic treatment were communicated to prescribers throughout the hospital by infectious diseases physicians working with Strama (the Swedish strategic programme against antibiotic resistance). No restrictive measures were used. The intervention effect was analysed with interrupted time series (ITS) regression analysis of local and national monthly antibiotic sales data.

RESULTS

A radical immediate and sustained reduction was demonstrated for the cephalosporins targeted in the intervention, whereas consumption of piperacillin/tazobactam and penicillin G increased substantially. Fluoroquinolone and carbapenem use was essentially unchanged. The ESBL outbreak subsided and no increased resistance to piperacillin/tazobactam was detected in K. pneumoniae, Escherichia coli or Pseudomonas aeruginosa blood isolates during the 2.5 year follow-up.

CONCLUSIONS

Our study clearly demonstrates that an educational intervention can have an immediate and profound effect on antibiotic prescription patterns at a large tertiary hospital. ITS regression analysis of local and national antibiotic sales data was valuable to readily assess the immediate and sustained effects of the intervention.

T cell control of primary and latent cytomegalovirus infections in healthy subjects

The T cell repertoire required to control acute and latent CMV infection in otherwise healthy individuals was examined using both functional analysis and a wide range of MHC I tetramers. Both frequency and function of CMV specific T cells varied considerably between subjects, however, within subjects values remained stable over time. In total 16 +/- 3.5 CMV specific T cells/mul blood was detected, with obvious immunodominance between different CMV epitopes. Most subjects with latent infection showed low CMV specific T cell activity, whereas a subgroup (1/3) of individuals was high in either frequency or function of their CMV specific T cells. Patients with acute infection displayed high initial, but rapidly decreasing, numbers of CMV specific cells. In conclusion, a majority of healthy individuals readily seem to control latent CMV infection, whereas a subpopulation (1/3) of individuals uses a large proportion of their CD8+ T cell repertoire to control the infection.

Genotypes of clustered cases of Pneumocystis carinii pneumonia

Reports of outbreaks of Pneumocystis carinii pneumonia (PCP) among human immunodeficiency virus-negative immunocompromised patients have suggested a person-to-person transmission of P. carinii. In this study, 17 bronchoalveolar lavage isolates from patients in 3 PCP outbreaks were genotyped, 2 in renal transplant recipients and 1 outbreak among patients with haematological disorders. Genotypes in the P. carinii sp. f. hominis (P. carinii f.sp. hominis) mt large subunit ribosomal RNA site 85 were detected by 2 methods: direct sequencing and 3 different allele-specific polymerase chain reaction assays. Although limited data on patient contacts were available, the detected P. c. hominis genotypes do not support person-to-person transmission as the predominant transmission route of P. carinii in humans.