Balloon-Guide Catheters Are Needed for Effective Flow Reversal during Mechanical Thrombectomy

BACKGROUND AND PURPOSE

Blood flow management in the carotid artery during mechanical thrombectomy is crucial for safety and effectiveness. There is an ongoing discussion about whether balloon-guide catheters or large-bore sheaths are needed for effective flow management. We compared general flow characteristics of proximal aspiration through a large-bore sheath and a balloon-guide catheter in a porcine in vivo model.

MATERIALS AND METHODS

We investigated blood flow in a porcine common carotid artery with and without aspiration (VacLok syringe and Penumbra pump, Pump MAX) through an 8F-long sheath and an 8F balloon-guide catheter. Blood hemodynamics were assessed via continuous duplex sonography.

RESULTS

Average vessel diameter and baseline blood flow were 4.4 ± 0.2 mm and 244 ± 20 mL/min, respectively. For the 8F sheath, pump aspiration resulted in a significant flow reduction (225 ± 25 mL/min, P < .001), but with a persisting antegrade stream. Manual aspiration resulted in collapse of the vessel in 2 of 7 measurements and oscillatory flow with antegrade systolic and retrograde diastolic components in the remaining 5 measurements. Net flow was antegrade (52 ± 44 mL/min) in 3 and retrograde (-95 ± 52 mL/min) in the remaining 2 measurements. For balloon-guide catheters, balloon inflation always resulted in flow arrest. Additional pump or manual aspiration resulted in significant flow reversal of -1100 ± 230 and -468 ± 46 mL/min, respectively (both, P < .001).

CONCLUSIONS

Only balloon-guide catheters allow reliable blood flow arrest and flow reversal in combination with aspiration via syringes or high-flow pump systems. Aspiration through an 8F sheath results in either collapse of the vessel or oscillatory flow, which can result in a net antegrade or retrograde stream.

Quality of life in elderly men with androgen deficiency

The partial androgen deficiency in aging male (PADAM) has been of great interest to investigators and the public in the last few years. For males, androgens are said to be essential for the maintenance of quality of life (QoL) but there are no data available with respect to QoL and PADAM yet. In order to evaluate changes of individual well-being of males older than 50 years and with subnormal levels of free testosterone (FT) (<200 pmol l(-1)), these men were asked to fill in a questionnaire regarding QoL. The objective of this study was to compare age-matched males with androgen deficiency (group 1; n = 24) and normoandrogenic elderly men (group 2; n = 24) with respect to QoL and somatic indicators of the endocrine status. Participants suffered from benign prostatic hyperplasia (BPH) and were hospitalized for prostate surgery. Health-related QoL was assessed by the SF-12 Health Survey, including the physical health index and the mental health index. The SF-12 was enlarged by the scales 'vitality' and 'psychological well-being' of the SF-36. Additionally, patients were asked about social and clinical items. There were no statistically significant differences between the two groups regarding social and clinical parameters. The physical health index was reduced in group 1 (P < 0.05; effect size was medium (d = 0.57)) whereas the mental health index was similar in both groups. The correlation between the two health indices was very low and not statistically significant (r = 0.05, P = 0.72). Patients of group 1 described a lower vitality compared to group 2 (P < 0.05), but no differences could be observed regarding psychological well-being. Therefore, androgen-deficient patients seem to have the impression of a reduced physical ability. Our data emphasize that the subjective description of health-related aspects of QoL is a very sensitive methodological approach to discover psychological differences between patients. For the differentiation between androgen-deficient patients and those with normal testosterone levels the physical health index seems to be more sensitive than the mental health index. A question of interest is whether this difference remains detectable if testosterone is supplemented to androgen-deficient men. Whether testosterone supplementation is beneficial to these patients has to be carefully considered.

Use of cartilage grafts in the treatment of laryngotracheal stenoses and defects in children

Stenosis of the laryngotracheal section is in most cases a sequel of intensive care treatment. Most of the children presenting with such stenoses need tracheostomy that in consequence impedes their physical, social and language development. Surgical treatment of stenosis and closure of tracheostomy as early as possible should be strived for. Reconstructive techniques using autogenous cartilage grafts have proved very effective. The aim of our study was to examine the influence of different methods on the structure and function of reconstructed airways. In 23 children between 2 and 16 years suffering from laryngotracheal stenosis we reconstructed the stenotic segments by insertion of autogenous cartilage grafts. Enlargement was achieved by cartilage implantation as a stent into the split cricoid plate in 16 children; in 3 cases we performed enlargement of the anterior wall and in 5 cases instable lateral walls of the trachea had to be reinforced. One child had to be treated with all three techniques at once. In another case the overstretched and soft posterior tracheal wall had to be stabilized. Enlargement of the cricoid plate has proved excellent in cases of a high degree of stenosis of the posterior commissure (Type III and IV of the Cotton classification). Subglottic stenoses Type II can be treated with anterior insertion of cartilage. The use of cartilage in surgical treatment of laryngotracheal stenosis in childhood leads to safe and sufficiently satisfactory results that do not hamper further development of either larynx or trachea.

S-Transnitrosylation of albumin in human plasma and blood in vitro and in vivo in the rat

S-Nitrosoalbumin (SNOALB) is the most abundant physiological circulating nitric oxide (NO) carrier regulating NO-dependent biological actions in humans. The mechanisms of its formation and biological actions are still incompletely understood. Nitrosation by authentic NO and S-transnitrosylation of the single sulfhydryl group located at Cys-34 of human albumin by the physiological S-nitroso compounds S-nitrosocysteine (SNOC) and S-nitrosoglutathione (GSNO) are two possible mechanisms. On a quantitative basis, we investigated by gas chromatography-mass spectrometry the contribution of these two mechanisms to SNOALB formation in human plasma and blood in vitro. GSNO and SNOC (0-100 microM) rapidly and efficiently (recovery=35%) S-transnitrosylated albumin to form SNOALB. NO (100 microM) S-nitrosated albumin to SNOALB at a considerably lower extent (recovery=5%). The putative NO-donating drugs glyceryl trinitrate and sodium nitroprusside (each 100 microM) failed completely in S-nitrosating albumin. Bubbling NO into human plasma and blood resulted in formation of SNOALB that inhibited ADP-induced platelet aggregation. Infusion of GS(15)NO in the rat resulted in formation of S(15)NOALB, [(15)N]nitrate and [(15)N]nitrite. Our results suggest that S-transnitrosylation of albumin by SNOC and GSNO could be a more favored mechanism for the formation of SNOALB in the circulation in vivo than S-nitrosation of albumin by NO itself.

Outcome of ICSI cycles using frozen-thawed surgically obtained spermatozoa in poor responders to ovarian stimulation: cancellation or proceeding to ICSI?

OBJECTIVE

To investigate the ICSI outcome of the patients who produced four follicles or less after ovarian stimulation using frozen-thawed surgically obtained spermatozoa.

STUDY DESIGN

The patient cohort of this study was composed of a carefully selected group of 20 men suffering from obstructive and non-obstructive azoospermia and in whom spermatozoa had been seen in their harvested epididymal aspirates and testicular tissues and the cryopreserved specimens had been used for subsequent ICSI cycles. This group of men represent those in whom the female partners produced only four follicles or less after ovarian stimulation.

RESULTS

For the cases of obstructive azoospermia with MESA (n=6) a total of nine cycles was carried out. Four couples went through one cycle, one couple underwent two cycles, one couple accomplished three cycles. Out of the nine cycles, seven went to embryo transfer. No pregnancy occurred in the MESA-ICSI group of patients. The mean+/-S.D. number of oocytes per cycle was 2.556+/-1.236, the mean+/-S.D. number of embryos per transfer was 1.444+/-1.014. Two couples did not have an embryo replacement because of absence of fertilisation. The mean+/-S. D. number of gonadotropin ampoules was 53.88+/-37.30 and the mean+/-S.D. duration of ovarian stimulation was 13.38+/-4.534 days. For the cases of non-obstructive azoospermia with TESE (n=14) a total of 16 cycles was carried out. Thirteen couples went through one cycle, one couple accomplished three cycles. Out of the 16 cycles, 11 cycles went to embryo transfer. One pregnancy occurred in the TESE-ICSI group of patients, which produced live offspring. The mean+/-S.D. number of oocytes per cycle was 3.00+/-1.211, the mean+/-S.D. number of embryos per transfer was 1.313+/-1.195. Five couples did not have an embryo replacement, four of them because of absence of fertilisation and one because of abnormal fertilisation (3 PN). The mean+/-S.D. number of gonadotropin ampoules was 81. 77+/-53.40 and the mean+/-S.D. duration of ovarian stimulation was 16.71+/-3.667 days.

CONCLUSION

In our opinion, these data show that it is possible to achieve satisfactory fertilisation rates using frozen-thawed epididymal and testicular spermatozoa obtained from men with obstructive or non-obstructive azoospermia, but the limiting factor in reaching the stage of embryo transfer is the poor ovarian response to stimulation induction. It therefore seems preferable to cancel these cycles, in the hope that a better response might be obtained in a subsequent cycle, avoiding in this way financial and emotional implications.

Endogenous nitric oxide synthase inhibitors are responsible for the L-arginine paradox

L-Arginine, the substrate of nitric oxide (NO) synthases (NOSs), is found in the mammalian organism at concentrations by far exceeding K(M) values of these enzymes. Therefore, additional L-arginine should not enhance NO formation. In vivo, however, increasing L-arginine concentration in plasma has been shown repeatedly to increase NO production. This phenomenon has been named the L-arginine paradox; it has found no satisfactory explanation so far. In the present work, evidence for the hypothesis that the endogenous NOS inhibitors methylarginines, asymmetric dimethylarginine being the most powerful (IC(50) 1.5 microM), are responsible for the L-arginine paradox is presented.

Assessment of nitric oxide synthase activity in vitro and in vivo by gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric method for the determination of nitric oxide synthase activity is described. The method is based on the gas chromatographic-mass spectrometric measurement of L-[15N2]arginine-derived [15N]nitrite as its pentafluorobenzyl derivative in the negative-ion chemical ionization mode. Application of the method to the analysis of [15N]nitrite formation by purified neuronal nitric oxide synthase revealed K(M) values of 3.1 microM by Hanes and 4.6 microM by Lineweaver-Burk for L-[15N2]arginine. The corresponding Vmax values were 0.204 and 0.228 micromol [15N]nitrite min(-1) mg(-1) NOS, respectively. N(G)-Nitro-L-arginine and N(G),N(G)-dimethylarginine (asymmetric dimethylarginine) were identified by this method as the most potent enzyme inhibitors. Nitric oxide synthase activity was also assessed in vivo by i.v. injection of L-[15N2]arginine in a rat and determination of plasma [15N]nitrite and [15N]nitrate. The assay described in this work allows for accurate, specific and highly sensitive determination of nitric oxide synthase activity in vitro and in vivo.

Electrospray ionization mass spectrometry of low-molecular-mass S-nitroso compounds and their thiols

Low-molecular-mass S-nitroso compounds (R-S-N=O) are potent vasodilators and inhibitors of platelet aggregation. This work describes the electrospray ionization mass spectrometric (ESI-MS) analysis of physiological and synthetic low-molecular-mass S-nitroso compounds and their thiols including S-nitrosoglutathione, S-nitrosocysteine, glutathione and cysteine. Mass spectra of the unlabeled and S-15N-labeled low-molecular-mass S-nitroso compounds investigated are characterized by abundant cations due to [M+H]+, [M+Na]+, [(M+H)-NO]+, [2 M+H]+, and [(2 M+H)-2NO]+. Mass spectra of low-molecular-mass thiols are characterized by abundant cations due to [M+H]+, [M+Na]+ and [2M+H]+. Using off-line electrospray ionization tandem mass spectrometry we unequivocally identified S-[15N]nitrosoglutathione in human red blood cells formed after their incubation with S-[15N]nitrosocysteine. These results suggest that ESI-MS in combination with an appropriate liquid chromatographic system should be a useful analytical approach for the on-line quantitative determination of low-molecular-mass S-nitroso compounds in biological fluids in the presence of their thiols and nitrite. Considerations were made about on-line ESI-MS and quantitative measurements.

Use of frozen-thawed testicular sperm for intracytoplasmic sperm injection

OBJECTIVE

To determine the feasibility of using frozen-thawed testicular spermatozoa for intracytoplasmic sperm injection.

DESIGN

Prospective clinical study.

SETTING

A university hospital.

PATIENT(S)

One hundred seventy-five azoospermic men participating in a routine intracytoplasmic sperm injection program.

INTERVENTION(S)

The men underwent testicular biopsy for cryopreservation of tissue to be used in consecutive intracytoplasmic sperm injection treatment cycles. Their female partners underwent controlled ovarian hyperstimulation for conventional IVF treatment.

MAIN OUTCOME MEASURE(S)

Fertilization and pregnancy rates.

RESULT(S)

In 77% of the patients, spermatozoa could be harvested from the testis by an open testicular biopsy technique and used for intracytoplasmic sperm injection after freezing and thawing of testicular tissue. Histopathologic evaluation revealed a Sertoli cell-only pattern in 21%, maturation arrest in 60%, and hypospermatogenesis in 19% of the patients. In 2. 9% of the patients, carcinoma in situ or a germ cell tumor was detected. In all patients, viable spermatozoa could be visualized after the tissue samples were thawed. One hundred thirty-five intracytoplasmic sperm injection treatment cycles were performed, with a fertilization rate of 45% and a clinical pregnancy rate of 30% per oocyte retrieved.

CONCLUSION(S)

The use of frozen-thawed testicular tissue allows ovarian stimulation of the female partner to be timed and avoids cancellation of ovum pick-up when spermatozoa cannot be retrieved.

Pressure and Temperature Dependence of the Decomposition Rate of Aliphatic tert-butyl Peroxyesters

The thermal decomposition in solution of

Intracytoplasmic injection of round and elongated spermatids from azoospermic patients: results and review

Microinjection is established as the method of choice in the treatment of severe male factor infertility as well as in azoospermic patients. Recent studies have shown that fertilization and cleavage can be achieved by injection of ejaculated as well as testicular elongated spermatids into oocytes. Here we report on the two first pregnancies worldwide resulting from elongated spermatid injection from frozen-thawed testicular tissue. Four patients with complete Sertoli cell-only syndrome (SCOS) and two with spermatogenetic maturation arrest were included in our microinjection programme. Tissues from open testicular biopsies were cryopreserved until the time of follicle puncture. A total of 67 oocytes were harvested. In the two patients with maturation arrest, cryopreserved elongated spermatids were successfully injected, while in two of the other four SCOS patients only cryopreserved round spermatids were available to be injected into the oocytes. Out of 18 injected oocytes, 10 were fertilized in the first group, while nine out of 49 injected oocytes showed fertilization and cleavage in the second group. Two clinical pregnancies were achieved with elongated spermatids from frozen-thawed testicular tissue, while no pregnancy was established in the case of round spermatids. This study confirms that fertilization, cleavage and pregnancy can be successfully achieved in cases with spermatogenetic maturation arrest by injecting cryopreserved elongated spermatids into oocytes. The literature on pregnancies following spermatid injection, as well as the problems using this technique and possible risks, are discussed.

Gas chromatographic-tandem mass spectrometric quantification of human plasma and urinary nitrate after its reduction to nitrite and derivatization to the pentafluorobenzyl derivative

Gas chromatography-mass spectrometry (GC-MS) of nitrite as its pentafluorobenzyl derivative in the negative-ion chemical ionization mode is a useful analytical tool to quantify accurately and sensitively nitrite and nitrate after its reduction to nitrite in various biological fluids. In the present study we demonstrate the utility of GC-tandem MS to quantify nitrate in human plasma and urine. Our present results verify human plasma and urine levels of nitrite and nitrate measured previously by GC-MS.

Determination of S-nitrosoglutathione in human and rat plasma by high-performance liquid chromatography with fluorescence and ultraviolet absorbance detection after precolumn derivatization with o-phthalaldehyde

An analytical method is described for the quantification of S-nitrosoglutathione (GSNO), a potent physiological vasodilator and inhibitor of platelet aggregation, in the presence of a high excess of reduced glutathione (GSH). The method is based on the quantitative elimination of GSH by N-ethylmaleimide, the conversion of GSNO by 2-mercaptoethanol to GSH, its reaction with o-phthalaldehyde (OPA) to form a highly fluorescent and UV-absorbing tricyclic isoindole derivative, and subsequent high-performance liquid chromatographic (HPLC) separation with fluorescence and/or UV absorbance detection. The OPA derivatives of GSH and GSNO obtained by this method were found to be identical by mass spectrometry. GSH (up to 50 microM) did not interfere with the analysis of GSNO (up to 1000 nM). The limits of detection of the method for buffered aqueous solutions of GSNO were determined as 3 nM using fluorescence and 70 nM using UV absorbance detection. Isolation of GSNO by HPLC analysis (pH 7.0) of plasma ultrafiltrate samples (200 microl) prior to derivatization allows specific and artifact-free quantification of GSNO in human and rat plasma. Reduced and oxidized glutathione, nitrite, and cysteine did not interfere with the measurement of GSNO in human and rat plasma. The limit of quantitation (LOQ) of the combined method was determined as 100 nM of GSNO in human plasma ultrafiltrate using fluorescence detection. No endogenous GSNO could be detected in ultrafiltrate samples of plasma of 10 healthy humans at concentrations exceeding the LOQ of the method. After iv infusion of GSNO (125 micromol/kg body wt) in a rat for 20 min GSNO and GSH were detected in rat plasma at 60 and 130 microM, respectively. The method should be useful to investigate formation, metabolism, and reactions of GSNO in vitro and in vivo at physiologically relevant concentrations.

Gas chromatographic-mass spectrometric detection of S-nitroso-cysteine and S-nitroso-glutathione

A gas chromatographic-mass spectrometric (GC-MS) method is described for the quantitative determination of the S-nitroso compounds S-nitroso-cysteine (SNC) and S-nitroso-glutathione (GSNO) using their (15)N-labeled analogs, i.e., S(15)NC and GS(15)NO, as internal standards. The method is based on the specific conversion by HgCl(2) of the unlabeled and (15)N-labeled S-nitroso groups to nitrite and (15)N-nitrite, respectively, and their conversion to the pentafluorobenzyl derivatives. The method was applied to quantify GS(15)NO formed in the cytosol of washed human erythrocytes incubated with S(15)NC. Combination of high-performance liquid chromatography with GC-MS allowed specific and accurate quantification of SNC and GSNO externally added to human plasma ultrafiltrate (range 0-10 microM). Method accuracy and precision for SNC and GSNO were close to 100 and below 9%, respectively. As little as 0.1 nM GS(15)NO corresponding to 30 amol of (15)N-nitrite injected onto the column was precisely detected by the method.

Effects of acute euglycemic hyperinsulinemia on urinary nitrite/nitrate excretion and plasma endothelin-1 levels in men with essential hypertension and normotensive controls

Insulin stimulates the production of endothelin-1 (ET-1) and nitric oxide (NO) by isolated endothelial cells. Additionally, insulin-dependent glucose transport and insulin-mediated NO production partially share common elements in signal transduction. There are discordant data on plasma ET-1 levels during acute euglycemic systemic hyperinsulinemia in normotensive men and men with essential hypertension (EH) (known to be insulin-resistant), as well as on the relations between insulin sensitivity and vascular function. Our aim was to assess the response of approximate measures of whole-body generation of NO and ET-1 to acute euglycemic hyperinsulinemia in EH patients and controls. We studied 17 newly diagnosed untreated men with uncomplicated EH and 10 normotensive controls. Plasma ET-1 and urinary excretion of nitrite plus nitrate, stable NO metabolites (Uno(x)), were measured before and during a 3-hour hyperinsulinemic-euglycemic clamp. Both in hypertensives and normotensives, plasma ET-1 levels were reduced after 2 hours of the clamp (EH: baseline, 3.1+/-1.9 pg/mL; 2 hours, 1.9+/-1.2 pg/mL, P = .04 v baseline; controls: baseline, 4.2+/-2.6 pg/mL; 2 hours, 2.8+/-1.4 pg/mL, P = .04 v baseline). No significant changes in Uno(x) during the clamp were observed. Changes in Uno(x) during the clamp (deltaUno(x)) and differences in plasma ET-1 measured before the end and before the beginning of the clamp (deltaET-1) were correlated in the controls (r = .75, P = .01) but not in EH (r = -.01, P = .97). No parameter of glucose metabolism correlated with basal Uno(x), basal plasma ET-1, deltaUno(x), and deltaET-1, whether absolute or percent values, in either group. Thus, acute euglycemic hyperinsulinemia produces a decrease in plasma ET-1 in both EH patients and controls. The lack of correlation between deltaUno(x) and deltaET-1 under these conditions in EH may suggest an impairment of systems governing interactions between the NO-dependent pathway and ET-1. In addition, insulin actions on glucose metabolism and on the endothelial mediators appear dissociated.

Interference by S-nitroso compounds with the measurement of nitrate in methods requiring reduction of nitrate to nitrite by cadmium

Various methods suited for the measurement of nitrate require its reduction to nitrite by cadmium under acidic or alkaline conditions. N(G)-Nitroarginine analogs have been shown to interfere with the measurement of nitrate by such assays. In the present work we show by gas chromatography-mass spectrometry that under alkaline reduction conditions the S-nitroso compounds S-nitrosoglutathione and S-nitrosohomocysteine but not S-nitroso-N-acetylcysteine and S-nitroso-N-acetylpenicillamine can considerably contribute to nitrate and thus interfere with its measurement. Our results suggest that S-nitroso compounds may interfere with the measurement of nitrate in methods requiring cadmium-catalyzed reduction of nitrate to nitrite.

Investigations of S-transnitrosylation reactions between low- and high-molecular-weight S-nitroso compounds and their thiols by high-performance liquid chromatography and gas chromatography-mass spectrometry

S-Transnitrosylation reactions are supposed to be the basic principle by which nitric oxide-related biological activities are regulated in vivo. Mechanisms of S-transnitrosylation reactions are poorly understood and equilibria constants for physiological S-nitroso compounds and thiols are rare. In the present study we investigated S-transnitrosylation reactions of the thiols homocysteine, cysteine, glutathione, N-acetylcysteine, N-acetylpenicillamine, and human plasma albumin and their corresponding S-nitroso compounds SNhC, SNC, GSNO, SNAC, SNAP, and SNALB utilizing high-performance liquid chromatographic and gas chromatographic-mass spectrometric techniques. These methods allowed to study S-transnitrosylation reactions in mixtures of several S-nitroso compound/thiol pairs, to determine equilibria constants, and to elucidate the mechanism of S-transnitrosylation reactions. We obtained the following order for the equilibria constants in aqueous buffered solution at pH 7.4: SNhC approximately SNAC > GSNO approximately SNALB > SNAP > SNC. Our results suggest that the mechanism of S-transnitrosylation reactions of these S-nitroso compounds and their thiols involve heterolytic cleavage of the S&sbond;N bond. Incubation of SNC with human red blood cells resulted in a dose-dependent formation of GSNO in the cytosol through S-transnitrosylation of intracellular GSH by the SNC transported into the cells. This reaction was accompanied with an almost complete disappearance of the SNC fraction transported into the cells. This finding is in full agreement with the equilibrium constant Keq of 1.9 for the reaction SNC + GSH <--> Cys + GSNO in aqueous buffer.

Measurement of S-nitrosoalbumin by gas chromatography-mass spectrometry. I. Preparation, purification, isolation, characterization and metabolism of S-[15N]nitrosoalbumin in human blood in vitro

S-Nitrosoalbumin (SNALB) and S-[15N]nitrosoalbumin (S[15N]ALB) were prepared by various methods, purified and isolated by a novel selective extraction procedure using HiTrapBlue Sepharose affinity columns and characterized by various techniques including SDS-PAGE electrophoresis, UV-Vis spectroscopy and gas chromatography-mass spectrometry (GC-MS). S-Nitrosylation of albumin in freshly obtained human plasma by unlabeled and 15N-labeled butylnitrite at neutral pH revealed the purest preparations. For GC-MS analysis, SNALB and S[15N]ALB were treated with HgCl2 to obtain nitrite and [15N]nitrite, respectively, which were then analysed as their pentafluorobenzyl derivatives. S[15N]ALB preparations were standardized by GC-MS using nitrite as internal standard. S[15N]ALB was prepared and isolated at concentrations of 188+/-43 microM (mean +/- SD, n = 8) at a final yield of about 45%, an isotopic purity of 98%, and SDS-PAGE electrophoretic purity of 90%. 15N-Labeled SNALB was used to study its metabolism in human blood. The half-life of S[15N]ALB (25 microM) in human heparinized blood in vitro was determined by GC-MS as 5.5 h. The GC-MS method described here could be useful for the quantitative determination of SNALB in human plasma using S[15N]ALB as an internal standard.

Measurement of S-nitrosoalbumin by gas chromatography-mass spectrometry. II. Quantitative determination of S-nitrosoalbumin in human plasma using S-[15N]nitrosoalbumin as internal standard

A gas chromatographic-mass spectrometric method for the quantitative determination of S-nitrosoalbumin (SNALB) in human plasma is described. The method is based on selective extraction of SNALB and its 15N-labeled SNALB analog (S15NALB) used as internal standard on HiTrapBlue Sepharose affinity columns, Hg2+ -catalysed conversion of the S-nitroso groups to nitrite and [15N]nitrite, respectively, followed by their derivatization to the pentafluorobenzyl derivatives and quantification by GC-MS. Mean recovery of SNALB and S15NALB from plasma was 45%. Mean precision and accuracy within the range 0-10 microM was 95% and 99%, respectively. The limit of quantitation was determined as 100 nM at a precision of 93.8% and an accuracy of 94.8%. Considerable improvement of method sensitivity is possible by eliminating nitrite present in the elution buffer. The limit of detection was 0.2 nM corresponding to 67 amol of S15NALB. In 0.4-ml aliquots of plasma samples from healthy humans, endogenous SNALB was determined at concentrations of 181+/-150 nM (mean +/- SD, n = 23). External addition of SNALB to these plasma samples at 2 microM and 5 microM serving as quality control samples resulted in quantitative recovery of SNALB. Our results show that SNALB occurs in human plasma at concentrations at least one-order of magnitude smaller than those reported in the literature from measurements using chemiluminescence.

Reduced urinary excretion of nitric oxide metabolites and increased plasma levels of asymmetric dimethylarginine in men with essential hypertension

Our aim was to investigate systemic nitric oxide (NO) production and its potential determinants such as insulin resistance, dyslipidemia, and circulating methylated analogs of L-arginine in uncomplicated essential hypertension (EH). Nineteen newly diagnosed, untreated male subjects with mild pure uncomplicated EH and 11 normotensive controls were studied at rest after an overnight fast. The groups had comparable age, body mass index, creatinine clearance, cholesterol, fasting glucose, and insulin. In hypertensives, the urinary excretion rate of nitrite plus nitrate (Unox), an index of endogenous NO production, was depressed (56+/-17 vs. 77+/-23 micromol/mmol creatinine; p < 0.05), whereas plasma levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis, were increased (2.4+/-1.1 vs. 1.1+/-0.7 microM; p < 0.005). Circulating concentrations of symmetric dimethylarginine were similar in both groups (1.4+/-1.3 vs. 1.5+/-1.1 microM; p = NS). The L-arginine-to-ADMA ratio was reduced in hypertension (3.3+/-0.5 vs. 4.5+/-0.8; p < 0.001 for In-transformed data). There was no correlation between Unox and either the magnitude of insulin resistance or dyslipidemia in EH. Thus in male subjects with EH, endogenous systemic NO formation appears depressed, which is unrelated to accompanying insulin resistance or dyslipidemia. Circulating ADMA levels are increased in uncomplicated EH, which may be of potential relevance.

High-performance liquid chromatographic analysis of nitrite and nitrate in human plasma as S-nitroso-N-acetylcysteine with ultraviolet absorbance detection

A rapid HPLC method with UV absorbance detection at 333 nm for the measurement of nitrite and nitrate in ultrafiltrate samples of human plasma is described. The method is based on hydrochloric acid-catalyzed conversion of nitrite by N-acetyl-L-cysteine to S-nitroso-N-acetyl-L-cysteine and isocratic elution using 10 mM NaH2PO4 in acetonitrile-water, pH 2.0 (15:85, v/v). The limit of detection of the method is 50 nM nitrite. The method was validated by gas chromatography-mass spectrometry.

Randomised placebo-controlled trial of moclobemide, cognitive-behavioural therapy and their combination in panic disorder with agoraphobia

BACKGROUND

In the treatment of panic disorder with agoraphobia, the efficacy of pharmacological, psychological and combined treatments has been established. Unanswered questions concern the relative efficacy of such treatments.

AIMS

To demonstrate that moclobemide and cognitive-behavioural therapy (CBT) are effective singly and more effective in combination.

METHOD

Fifty-five patients were randomly assigned to an eight-week treatment of: moclobemide plus CBT; moclobemide plus clinical management ('psychological placebo'); placebo plus CBT; or placebo plus clinical management.

RESULTS

Comparisons between treatments revealed strong effects for CBT. Moclobemide with clinical management was not superior to placebo. The combination of moclobemide with CBT did not yield significantly better short-term results than CBI with placebo. The CBT results remained stable during a six-month follow-up, although a substantial proportion of patients treated with placebo plus CBT needed additional treatment.

CONCLUSIONS

CBT was highly effective in the treatment of panic disorder with agoraphobia and reduced agoraphobia to levels that were comparable to those of non-clinical controls.

Fluvoxamine or placebo in the treatment of panic disorder and relationship to blood concentrations of fluvoxamine

A six-week double-blind placebo-controlled trial of fluvoxamine was undertaken in 46 patients suffering from panic disorder with or without agoraphobia diagnosed by DSM-III-R guidelines. Average daily dosage of fluvoxamine was 160 mg, with a highest permitted dose of 300 mg/day. Weekly evaluation included a diary in which the number, severity, and duration of full-blown and limited panic attacks and the duration and severity of anticipating fear, CAS, GAS, CGI, HAM-D, adverse effects and the number of capsules not taken were noted. Fluvoxamine was not significantly superior to placebo with regard to the main outcome criterion, i.e., the reduction in the number of panic attacks, but it was significantly more effective with regard to the diminution in the number of limited panic attacks and showed a tendency to significance in respect of GAS and CGI. Plasma levels of fluvoxamine were measured at the end of week one and at the end of the study. Most patients with complete remission at the end of the study were found in the verum group with plasma fluvoxamine levels ranging from 10 to 100ng/ml. It is suggested that therapeutic response might be maximized by monitoring fluvoxamine concentrations in blood.

Analysis of cysteine and N-acetylcysteine in human plasma by high-performance liquid chromatography at the basal state and after oral administration of N-acetylcysteine

A high-performance liquid chromatographic method for the determination of free reduced cysteine and N-acetylcysteine in human plasma at the basal state and after oral administration of N-acetylcysteine is described. The method is based on acid-catalysed conversion of plasma thiols to the corresponding S-nitroso derivatives by excess of nitrite and their subsequent cation-pairing RP-HPLC with detection at 333 nm. Recovery rates of cysteine and N-acetylcysteine added to human plasma were 94.6 and 99.6%, respectively. Inter- and intra-day precision were below 6%. In healthy humans (n = 5), free reduced cysteine was determined to be (mean+/-S.E.) 10.0+/-0.96 microM. No N-acetylcysteine was detected in plasma of these subjects above the limit of detection (e.g. 170 nM). The method was successfully applied to a pharmacokinetic study on orally administered N-acetylcysteine to healthy volunteers.

Public opinion on psychotropic drugs: an analysis of the factors influencing acceptance or rejection

Widespread negative attitudes and irrational beliefs about psychotropic drugs held by the public affect patients' treatment compliance. This study was an attempt to identify factors influencing people's acceptance or rejection of psychotropic drugs. An opinion poll was taken by a representative group of 2,176 adults in Germany. In addition to their attitudes toward psychotropic and cardiac drugs and their ratings of perceived risks and benefits, they were also asked about their drug knowledge, their fear of losing self-control, and their fundamental political values. Our results show that even for the treatment of severe mental disease, psychotropic drugs generally are not well accepted compared to cardiac drugs. Psychotropic drugs are believed to cause significantly more severe side effects and provoke more fear of losing control compared with cardiac drugs. Knowledge about psychotropic drugs and experiences with patients suffering from mental disorders are rather limited. Therefore, other sources of information such as negatively tainted reports in the mass media have a significant impact on opinions about psychotropic drugs. Unexpectedly, negative media reports are even more important for the discrimination of distinct subtypes like "acceptors" and "rejecters" of psychotropic drugs than fundamental value orientation. It is recommended that educational and information measures must be enacted to achieve balanced presentation of psychotropic drugs, their effects, and their side effects in the mass media. Improved communication and linguistic elements used in psychotherapeutic settings should be integrated into biological psychiatry to improve understanding of the concepts of mental diseases and their treatment.

Measurement of nitrite and nitrate in biological fluids by gas chromatography-mass spectrometry and by the Griess assay: problems with the Griess assay--solutions by gas chromatography-mass spectrometry

Assay methods based on the Griess reaction are frequently used to measure nitrite and nitrate in urine, plasma, and other biological fluids. With minor exceptions, careful attention has not been paid in extending the Griess assay from aqueous solutions to biological fluids, In the present study, parallel measurements of nitrite and nitrate were performed in urine, plasma, and aqueous solutions with a published batch assay based on the Griess reaction and with gas chromatography-mass spectrometry (GC-MS). We report here further interferences by free reduced thiols, proteins, and other plasma constituents in the Griess assay but not in GC-MS. The best correlation (r2 = 0.985) between the Griess assay and GC-MS was observed for aqueous solutions in the absence of thiols. Unlike GC-MS, the Griess assay was not applicable to whole human plasma and urine samples. For the measurement of nitrate in diluted human urine samples, reduction by cadmium was performed both under acidic (pH 2 or 5) and alkaline (pH 8.8) conditions. The mean recovery rate of nitrate from urine samples was quantitative in the GC-MS but amounted to only 30-80% in the Griess assay. Measurement of nitrate in human urine samples (n = 33) resulted in an excellent correlation between two GC-MS techniques (r2 = 0.979) but only in a poor correlation (r2 < 0.64) between the Griess assay and GC-MS. Unlike GC-MS, the batch Griess assay is associated with many problems in measuring nitrate in biological fluids.

Tamm-Horsfall protein inhibits binding of S- and P-fimbriated Escherichia coli to human renal tubular epithelial cells

Escherichia coli is the predominant pathogen in urinary tract infections. Fimbriae are one of the major virulence factors of these bacteria, since these protein appendices contribute towards bacterial adhesion to epithelial cells. In clinical E. coli isolates from urinary tract infections, P fimbriae are more frequently present than S fimbriae. However, these two types of fimbriae mediate adhesion to cultured tubular epithelial cells equally well. Tamm-Horsfall protein, which is the most abundant protein in normal human urine, inhibits hemagglutination by E. coli expressing S fimbriae, but does not interfere with hemagglutination by P-fimbriated E. coli. Therefore, it has been speculated that Tamm-Horsfall protein may serve as a clearance factor for S-fimbriated E. coli in human urine. In our experiments, adherence of purified S fimbriae and of S-fimbriated E. coli to tubular epithelial cells was inhibited by Tamm-Horsfall protein, but the protein also decreased binding of P-fimbriated E. coli to approximately the same degree. We found less adherence of both types of fimbriae to a Madin-Darby canine kidney cell line expressing soluble and membrane-bound Tamm-Horsfall protein as compared with the control cell line. In conclusion, our in vitro data suggest that urinary Tamm-Horsfall protein may serve as a clearance factor for E. coli expressing both S and P fimbriae. In the light of these findings, the low clinical relevance of S-fimbriated E. coli for urinary tract infections may be readily explained; however, the predominance of P fimbriae remains unresolved.

Psychopharmacological drugs as represented in the press: results of systematic analysis of newspapers and popular magazines

The representation of mental diseases and psychopharmacological drugs in the media, especially in the press, is thought to be of great impact on people's opinions on the subject. During the course of one year, all articles about psychopharmacological drugs and cardiac drugs published in nineteen German newspapers were collected. All statements, together with related aspects, reasons for prescription, individual details of the patient, effects and side-effects, were registered and classified according to a key. The results show that, in contrast to 13% of the articles about cardiac drugs, half of the reports about psychopharmacological drugs deal primarily with the problems of side-effects and dependence the drugs may produce. There was much more critical comment and emotional emphasis used to characterize the psychopharmacological drugs. Only in 9% of articles was their therapeutic efficacy mentioned. Cardiac drugs are generally discussed objectively in a medical context and in 53% efficacy is emphasized. Psychopharmacological drugs are often mentioned in stories about prominent persons having a life crisis, taking drugs, turning to alcoholism, or in the context of social decline. Only in 3% of all articles about psychopharmacological drugs was it possible to identify a serious mental disease as the reason for prescription. The reasons for and implications of these findings, which mainly reflect the negatively biased image of psychopharmacological drugs in women's magazines (while they are treated relatively fairly in general newspapers) are discussed.

[Psychopharmaceutical drugs in the mass media. Results of a systematic analysis of text contents and images]

Mental diseases and psychopharmacological drugs are frequently discussed in newspapers and popular magazines. The representations are supposed to have a great impact on people's opinions on the subject. From 1 August 1991 to 31 July 1992 all articles about psychopharmacological drugs and cardiac drugs in 19 German newspapers were collected. All statements, effects and side effects, the reason for prescription, individual details about the patient and, according to this procedure, subjects and implications of the illustrations, were registered and classified according to a code book. In contrast to the articles about cardiac drugs, half of the psychopharmacological drug reports primarily deal with the problems of side effects the drugs may produce. There was much more critical comment and emotional emphasis used to characterize the psychopharmacological drugs. Only in 9% was their therapeutic efficacy mentioned. Cardiac drugs are generally discussed objectively in a medical context and their efficacy is emphasized. Psychopharmacological drugs are often mentioned in stories about prominent persons having a life crisis, taking drugs, or turning to alcoholism, in the sense of social decline. In only 3% of these articles could a serious mental diseases be identified as the reason for the prescription. Corresponding to the more prominent emotional emphasis of these articles, compared to the articles about cardiac drugs, more pictures, mainly of prominent persons or patients are used. However, the illustration seldom adds to information provided. The reasons for and implications of these findings and the significant differences between the distinct groups of newspapers are discussed.

Mechanisms of phospholipase D stimulation by m3 muscarinic acetylcholine receptors. Evidence for involvement of tyrosine phosphorylation

In human embryonic kidney cells stably expressing the human m3 muscarinic acetylcholine receptor (mAChR) subtype, agonist (carbachol) activation stimulated phospholipase C, increased cytoplasmic calcium concentration, induced tyrosine phosphorylation of various cellular proteins and activated phospholipase D. Bypassing membrane receptors, phospholipase D was activated in these cells by direct activation of protein kinase C by phorbol esters, by direct activation of GTP-binding proteins by A1F4- and a stable GTP analogue (in permeabilized cells), by increasing cytoplasmic calcium concentration with the calcium ionophore A23187 and also apparently by tyrosine phosphorylation. In order to identify possible mechanisms by which the m3 mAChR couples to phospholipase D, various inhibitors of protein kinase C, tyrosine kinases and calcium-dependent events were studied. Prevention of an agonist-induced increase in cytoplasmic calcium concentration did not alter the mAChR-induced phospholipase D stimulation. The protein kinase C inhibitors, calphostin C and staurosporine, efficiently prevented phospholipase D activation by phorbol 12-myristate 13-acetate but only partially inhibited the activation induced by the mAChR agonist. Additionally, down-regulation of protein kinase C by prolonged exposure to phorbol 12-myristate 13-acetate abrogated phospholipase D activation by this effector but had only minor or no effects on the response to the mAChR agonist and direct activators of GTP-binding proteins. In contrast, the tyrosine kinase inhibitor genistein abolished the carbachol-induced and A1F4(-)-induced phospholipase D activation but had no effect on enzyme activation by phorbol 12-myristate 13-acetate. The data indicate that phospholipase D in m3 mAChR-expressing human embryonic kidney cells can be activated by various different mechanisms, i.e. receptor agonists, GTP-binding proteins, protein kinase C-dependent and calcium-dependent events and tyrosine phosphorylation. The coupling of m3 mAChR to phospholipase D appears to be largely independent of concomitant phospholipase C activation with subsequent increase in cytoplasmic calcium concentration and protein kinase C activity. The data instead suggest the involvement of an essential protein tyrosine phosphorylation mechanism in phopsholipase D activation by the m3 mAChR and heterotrimeric GTP-binding proteins.

Transfected muscarinic acetylcholine receptors selectively couple to Gi-type G proteins and Gq/11

Regulation of effector functions by muscarinic acetylcholine receptor subtypes is mediated by pertussis toxin-sensitive and -insensitive G proteins. In membranes from human embryonic kidney 293 cells transfected with m1, m2, and m3 muscarinic acetycholine receptors, we detected the pertussis toxin-sensitive G proteins Gi1, Gi2, and Gi3 and the pertussis toxin-insensitive G proteins Gq/11 and Gs. Subtype-specific immunoprecipitation of G protein alpha subunits photolabeled with [alpha-32P] GTP azidoanilide, in the absence and presence of carbachol, revealed the selective coupling of activated muscarinic receptors to G protein subtypes. Gq/11 was activated via m1 and m3 receptors and Gi2 was activated via m2 receptors. All three receptors subtypes mediated the activation of Gi1 and Gi3. Effective activation of Gi1 and Gi3 via m1 and m3 receptors occurred only at high carbachol concentrations (EC50 about 10-20 microM), whereas carbachol with higher potency (EC50 about 1 microM) induced activation of all G1 subtypes via m2 receptors. Thus, coupling of muscarinic receptors and G protein subtypes was principally selective; however, activation of distinct G protein subtypes by different muscarinic receptors occurred with different efficacies.

[Attitude of medical students to treatment with psychotropic drugs. 1: Comparison between medical students and the general population]

The attitudes of medical students towards psychotropic drugs are compared with those of the general public. Students strike a more positive balance between the costs and benefits of this treatment method. Whereas there are no marked differences as concerns desirable effects both groups differ considerably in the assessment of the limitations and risk of undesirable side-effects with students being less sceptical in this respect. Also with regard to other attitudinal domains student's judgement is more favourable. However, this does not mean that there is not a remarkably large group which articulates reservations against the use of psychotropic drugs. Whereas the majority of the lay public considers psychotherapy in general as superior to psychopharmacotherapy most students tend to differentiate between the various forms of psychiatric disorder.

[Attitude of medical students to treatment with psychotropic drugs. 2: Change in attitude in the course of medical education]

Advanced medical students' attitude to psychotropic drugs is more positive than the lay public's view on that subject (see part I). The question arises if this is a result of the psychiatric and psychopharmacological knowledge students have acquired during their medical education or an effect of selection by which students already have a more positive opinion of psychotropic drugs before the commencement of their medical education. Our survey in three differently advanced groups of medical students (n = 323) was carried out with a questionnaire. In contrast to their scepticism concerning psychopharmacological treatment students in the beginning of their medical education estimate others than psychotropic drugs ly than the lay public. This may be explained by a beginning identification with the model of a quickly and effectively treating doctor. In the course of medical and especially psychiatric and psychopharmacological education, there is a tendency to a more differentiated and positive view on the effects of psychotropic drugs although the generally critical attitude persists.

Reinvestigation of the transitional epithelium (urothelium) of the human ureter

The transitional epithelia (urothelia) of the ureters of 30 patients of different ages were studied by means of light and electron microscopical, histochemical and immunocytochemical methods. A great variability of the normal structural appearance of the urothelium was established. Structural features and the uptake of exogenous peroxidase by the surface epithelial cells provided high endocytotic activity. Urothelial cells take up many low and high molecular weight substances from the urine and further metabolize and transport these toward the subepithelial connective tissue. Lymphocytes, macrophages, monocytes, plasma cells and rarely polymorphonuclear leukocytes are distributed intra- and extraepithelially and are involved in the immunological response to agents which enter the intercellular spaces of the epithelium. These cells are also responsible for the elimination of aged and degenerating superficial squamous cells. The present investigation establishes the existence of immunological defence mechanisms in the adult human urothelium. The results obtained suggest that the human ureter contains three functional barriers directed against aggressive components of the urine: the first represented by structures of the superficial squamous cells, the second by the upper cells of the ureteric intermediate layer and the third comprising epithelial and immunological cells involved in immune defence mechanisms.

[Validation of diagnoses according to psychiatric diagnostic manuals in follow-up studies, exemplified by affective and schizophrenic diseases]

The new international classification schedules ICD-10 and DSM-III-R were developed by committees of experts. These schedules need to be validated. One strategy is to conduct prospective long-term follow-up studies recruiting patients with a broad variety of syndromes diagnosed initially by previous and more recent classification schedules. Studies following this strategy are discussed and a new two-year follow-up study is presented. Several modifying psychosocial and treatment factors and methodological problems impose limitations on the interpretation of those studies with regard to the validity of applied classification schedules. Alternative validation strategies are discussed.

[Fibromuscular dysplasia as a cause of cerebral infarct]

Fibromuscular dysplasia (FMD) is a non-atheromatous, non-inflammatory, segmental arteriopathy of unknown etiology. Fibroplasia of the tunica media is most common. After the renal arteries, the carotid arteries are most frequently affected. Angiographically beaded and tubular stenoses are seen. Complete occlusions and spontaneous dissection of the carotid arteries occur. The angiopathy causes general symptoms such as headache and vertigo, but also recurrent TIA and ischemic cerebral infarction. We examined 15 patients (12 female) suffering from FMD and stroke. The diagnosis of FMD was based on angiographic findings in all cases. 13 patients made a good recovery and seven of them could be discharged from hospital without any neurological deficit. Apart from conservative treatment, primary percutaneous or operative angioplasty may be necessary in some cases in spite of the mostly benign outcome of the disease. Acetylsalicylic acid should be given in all cases.

Coupling of transfected muscarinic acetylcholine receptor subtypes to phospholipase D

Muscarinic receptor-induced changes in the activities of phospholipase D (PLD) and of phosphoinositide-phospholipase C (PI-PLC) were investigated in human embryonic kidney (HEK) cells transfected with, and stably expressing, the human m1, m2, m3, and m4 mAChR subtypes, respectively. PLD and PI-PLC activities in these four transfected cell lines as well as in nontransfected cells were measured by the formation of [3H]phosphatidylethanol [( 3H]PEt) and [3H]inositol phosphates [( 3H]IP) after labeling cellular phospholipids with [3H]oleic acid and [3H]inositol. The muscarinic receptor agonist carbachol had no significant effects on [3H]PEt and [3H]IP formation in nontransfected HEK cells. In cells expressing the m1 or m3 receptors carbachol (1 mM; in the presence of 400 mM ethanol and 10 mM lithium chloride) caused the formation of [3H]PEt of about 12,000 cpm/mg protein (basal PEt formation was not measurable) and increased [3H]IP formation by 20,000-30,000 cpm/mg (a 7-10-fold increase over basal levels). The EC50 values (0.3-1.5 microM) were similar for both effects and both mAChR subtypes. In contrast, in cells expressing m2 or m4 receptor subtypes the magnitude of [3H]PEt (about 4,000 cpm/mg protein) or [3H]IP (3,000-4,000 cpm/mg) formation was much smaller and the EC50 values (20-40 microM) much higher than for the m1 and m3 receptors. Neomycin (1 mM) inhibited the m1 and m3 receptor-mediated production of IP by 50%, whereas the PEt formation was attenuated by 20% in the same cells. We conclude that activation of all of the four mAChR subtypes, although with different efficiencies, can stimulate PLD. The m1 and m3 receptor-mediated stimulation of the PLD may be at least partially independent of the PI-PLC stimulation.

Stimulation of phospholipase D activity in human neuroblastoma (LA-N-2) cells by activation of muscarinic acetylcholine receptors or by phorbol esters: relationship to phosphoinositide turnover

We have investigated the coupling of muscarinic acetylcholine receptors (mAChR) to phospholipid hydrolysis in a human neuroblastoma cell line, LA-N-2, by measuring the formation of 3H-inositol phosphates (3H-IP) and of [3H]phosphatidylethanol ([3H]PEt) in cells prelabeled with [3H]inositol and [3H]oleic acid. The muscarinic agonist carbachol (CCh) stimulated the phospholipase C (PLC)-mediated formation of 3H-IP in a time- and dose-dependent manner (EC50 = 40-55 microM). In addition, in the presence of ethanol (170-300 mM), CCh elevated levels of [3H]PEt [which is regarded as a specific indicator of phospholipase D (PLD) activity] by three- to sixfold. The effect of CCh on PEt formation also was dose dependent (EC50 = 50 microM). Both effects of CCh were antagonized by atropine, indicating that they were mediated by mAChR. Incubation of LA-N-2 cells with the phorbol ester phorbol 12-myristate 13-acetate (PMA, 0.1 microM; 10 min) increased [3H]PEt levels by up to 10-fold. This effect was inhibited by the protein kinase C (PKC) inhibitor staurosporine (1 microM) or by pretreatment for 24 h with 0.1 microM PMA, by 74% and 65%, respectively. In contrast, the effect of CCh on PEt accumulation was attenuated by only 28% in the presence of staurosporine (1 microM). In summary, these results suggest that, in LA-N-2 neuroblastoma cells, mAChR are coupled both to phosphoinositide-specific PLC and to PLD. PKC is capable of stimulating PLD activity in these cells; however, it is not required for stimulation of the enzyme by mAChR activation.

[Acute paraparesis in chronic hepatic disease]

An acuta caude equina syndrome following portacaval shunt in a 64-year-old patient suffering from liver cirrhosis is reported. Diagnosis of a hepatic radiculopathy was confirmed by clinical and electrophysiological findings. A nearly complete remission of the neurological symptoms was achieved by treatment of the primary liver disease. Since there are only a few descriptions of severe hepatic polyneuro- and radiculopathies, the differential diagnosis of hepatic myelopathy is discussed.

[Mollaret benign recurrent aseptic meningitis. Case report, results of cerebrospinal fluid cytology and review of the literature]

Mollaret's recurrent aseptic meningitis is a rare disease of unknown etiology and excellent prognosis, characterized by short attacks of meningeal irritation, fever and pleocytosis with first polymorphonuclear, then mononuclear predominance. A case is reported, in which the characteristic so-called endothelial cells in the CSF were identified as monocytes with immunocytochemic methods. The remaining fraction of CSF cells mainly consisted of T-lymphocytes with a majority of CD4 positive cells and an increased portion of CD38 positive cells. Between attacks, patients are asymptomatic. The course is self-limiting. Specific treatment is unknown.

Positron emission tomography in Creutzfeldt-Jakob disease

Regional cerebral glucose metabolism was studied in a 73-year-old woman with autopsy-confirmed Creutzfeldt-Jakob disease, using positron emission tomography of 2-(18F)fluorodeoxyglucose. Regional absolute values were analyzed in 14 partially overlapping slices. Clinically, the patient was in an advanced stage of disease when positron emission tomographic scans revealed severe, diffuse hypometabolism, and neuropathological findings showed diffuse spongiform changes throughout the brain, with neuronal cell loss being obvious only in the cerebellum. Computed tomography was unremarkable for age, whereas the positron emission tomographic results were in accordance with histological findings and the patient's clinical condition. This article suggests that positron emission tomography depicts neuronal dysfunction rather than neuronal cell loss.