Individualised prediction of drug resistance and seizure recurrence after medication withdrawal in people with juvenile myoclonic epilepsy: A systematic review and individual participant data meta-analysis

BACKGROUND

A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after achieving seizure-freedom. It is currently impossible to predict who is likely to become drug-resistant and safely withdraw treatment. We aimed to identify predictors of drug resistance and seizure recurrence to allow for individualised prediction of treatment outcomes in people with JME.

METHODS

We performed an individual participant data (IPD) meta-analysis based on a systematic search in EMBASE and PubMed - last updated on March 11, 2021 - including prospective and retrospective observational studies reporting on treatment outcomes of people diagnosed with JME and available seizure outcome data after a minimum one-year follow-up. We invited authors to share standardised IPD to identify predictors of drug resistance using multivariable logistic regression. We excluded pseudo-resistant individuals. A subset who attempted to withdraw ASM was included in a multivariable proportional hazards analysis on seizure recurrence after ASM withdrawal. The study was registered at the Open Science Framework (OSF; https://osf.io/b9zjc/).

FINDINGS

Our search yielded 1641 articles; 53 were eligible, of which the authors of 24 studies agreed to collaborate by sharing IPD. Using data from 2518 people with JME, we found nine independent predictors of drug resistance: three seizure types, psychiatric comorbidities, catamenial epilepsy, epileptiform focality, ethnicity, history of CAE, family history of epilepsy, status epilepticus, and febrile seizures. Internal-external cross-validation of our multivariable model showed an area under the receiver operating characteristic curve of 0·70 (95%CI 0·68-0·72). Recurrence of seizures after ASM withdrawal (n = 368) was predicted by an earlier age at the start of withdrawal, shorter seizure-free interval and more currently used ASMs, resulting in an average internal-external cross-validation concordance-statistic of 0·70 (95%CI 0·68-0·73).

INTERPRETATION

We were able to predict and validate clinically relevant personalised treatment outcomes for people with JME. Individualised predictions are accessible as nomograms and web-based tools.

FUNDING

MING fonds.

Is it Possible to Provide a Prognosis after Radical Prostatectomy for Prostate Cancer by Means of a Psa Regression Model?

Background

For over 15 years, studies have been done to evaluate the elimination kinetics of the prostate-specific antigen (PSA) after radical prostatectomy. Even though evaluation of PSA regression in the two-compartment model has become established, no clear data are currently available as to whether a statement can be made with regard to tumor prognosis from a computation of the PSA half-life (PSA-HL). This study focuses on the determination of the PSA-HL in the two-compartment model and on its correlation with the biochemical recurrence-free survival. In addition, a computer program is being developed to simplify the determination of PSA-HL.

Material and methods

Seventy-seven prospective patients were examined who subsequently had a radical prostatectomy at our facility without neoadjuvant or adjuvant hormone deprivation. In addition to preoperative measurement of the PSA value (d0), PSA determinations were carried out postoperatively on days 5, 10 and 60, and at four-monthly intervals thereafter (mean follow-up: 16 months). By means of the computer program developed for this purpose, CTK. TumW, the PSA half-lives for the first (d0–d5, PSA-HL1) and second (d5–d10, PSA-HL2) compartments were subsequently determined and their effect on biochemical recurrence-free survival was assessed.

Results

PSA-HL1 and PSA-HL2 were 1.89 (± 0.03) and 3.39 (± 0.14) days, respectively. Whilst PSA-HL1 did not permit any prognostic statement, the median PSA-HL in the second compartment between patients with and without disease progression differed significantly (4.44 versus 3.12 days; p<0.001). Discrimination analysis produced a cutoff of 3.8 days for the second compartment; patients with a PSA-HL2 ≥3.8 days had a significantly worse biochemical recurrence-free survival after 18 months than the other patients (27% versus 93%; p<0.001).

Conclusion

The PSA regression kinetics after radical prostatectomy follows a two-compartment model in which the prognostic value of the PSA-HL1 is limited. When a cutoff of 3.8 days is used, evaluation of the PSA-HL in compartment 2 (d5–10) appears to permit a prognostic statement. Due to the limited postsurgical follow-up, the disease process was only assessed as biochemical recurrence-free survival, and a longer follow-up will be necessary to generate data on progression-free survival.

Fallgruben in der Magnetresonanztomographie

The constantly extending indication spectrum of magnetic resonance imaging (MRI) is a challenge for the anaesthesiologist, who is being increasingly more consulted for assistance during the examination. Due to the special technology of MRI the anaesthetic technique differs substantially from that in the operating theatre. In addition to the permanent strong magnetic field the intermittently used high frequency impulses are also a potential danger for the patient. Patients with metal implants (e.g. cardiac pacemaker) are particularly at risk. For the safe treatment of patients during MRI a special MRI compatible anaesthesia equipment is necessary. Unsuitable devices can lead to malfunctioning or to projectile effects (attracting ferromagnetic objects into the magnet) causing injury to the patients. This paper describes the MRI technology and the associated dangers for the patient as well as the characteristics of the anaesthetic techniques.

[A benign abdominal schwannoma presenting as postrenal failure--a case report]

BACKGROUND

Benign schwannomas are uncommon soft-tissue tumors in childhood. The occurrence of an abdominal schwannoma effecting an acute postrenal failure has not been reported thus far.

PATIENTS

It is to describe the case of a 14-year-old male teenager who was admitted to our department because of inappetence and oedema in his face and on both feet. Further diagnostic investigations demonstrated a 24x20x15 cm abdominal tumor, which lead to an acute postrenal failure. The resection of the intraperitoneal tumor was performed completely, the histopathological examination revealed a benign schwannoma. Subsequently, the renal function had rapidly to normalised and ten years after the operation he has had no tumor recurrence.

CONCLUSIONS

Surgical excision in toto is the treatment of choice. The clinical presentation, differential diagnosis and operative strategy for benign and malignant abdominal schwannomas are discussed.

Body size and weight as predisposing factors in varicocele

OBJECTIVE

The literature regarding the constitutional type of children and adolescents with varicocele is inconsistent. The aim of this investigation was to examine a possible influence of weight, height and body mass index (BMI) on the formation of varicoceles during childhood and adolescence.

MATERIAL AND METHODS

In a retrospective data analysis, 193 Caucasian children and adolescents aged 9-19 years (mean age 14.7 years) with left-sided varicocele grade 2-3 were studied. The weight, height and BMI of the subjects were compared with the age-correlated normal values currently accepted in Germany. Additionally, the familial disposition for varicocele and the occurrence of relevant concurrent diseases were considered.

RESULTS

In the group of patients examined, the mean percentiles of weight (57th) and height (58th) were significantly above and the mean BMI percentile (42th) was significantly below the age-correlated 50th percentile for the normal population (p=0.019, 0.005 and 0.002). In our case material, 12.2% of all brothers of the patients had varicoceles.

CONCLUSIONS

The results of this investigation suggest a correlation between physical appearance and the formation of a varicocele during childhood or adolescence. We were able to demonstrate that patients with varicocele were heavier and taller than an age-correlated normal population, but had a distinctly lower BMI. Further studies are needed to verify whether this rather athletic habitus, together with the postulated difference in muscle:fat ratio, represents an important etiologic factor for varicocele formation.

Effect of mycophenolate mofetil on IMP dehydrogenase after the first dose and after long-term treatment in renal transplant recipients

OBJECTIVE

Mycophenolate mofetil (MMF) is routinely used as an immunosuppressant in a fixed daily dose regimen although it shows marked fluctuations in pharmacokinetics, and despite the fact that in regard to the active metabolite, mycophenolic acid (MPA), there is a well-known association between the pharmacokinetic parameters and clinical outcome.

METHOD

In order to determine the time course and the variability in cellular target of MPA after renal transplantation, we investigated the pharmacodynamic response in 8 patients receiving 1 g MMF for the first time prior to renal transplantation and in 8 stable renal transplant patients maintained on long-term MMF therapy (1 g b.i.d.) for more than 1 year. The pharmacodynamic response was measured using inosine 5'-monophosphate dehydrogenase (IMPDH) activity in peripheral mononuclear cells. MPA plasma concentrations were measured in parallel, IMPDH activity in 89 healthy blood donors was used as a control.

RESULTS

We observed a high interindividual variability in IMPDH activity in the 89 untreated healthy volunteers (4.0 - 32.9 nmol/h/mg protein), in 8 patients on dialysis (5.3 - 18.9 nmol/h/mg protein) and in 8 renal transplant patients under long-term MMF treatment (2.3 - 14.4 nmol/h/mg protein). The mean AUC0-12h for mycophenolic acid was 2-fold higher in patients receiving long-term treatment with MMF (62.2 +/- 16.6 mg x h/ml) compared to dialysis patients receiving 1 g MMF for the first time (31.5 +/- 15.6 mg x h/ml). Despite this pharmacokinetic difference there were no statistically significant differences in the cellular pharmacodynamic response. Minimal IMPDH activity (1.62 +/- 1.23 vs. 1.77 +/- 1.49 nmol/h/mg protein) and maximal IMPDH inhibition (87.5 +/- 0.08 vs. 77.4 +/- 18.8%) during the dosing interval were similar.

CONCLUSIONS

The considerable interindividual variability in the pharmacokinetics of MMF as well as in the drug target support the use of pharmacodynamic drug monitoring to optimize MMF dosing and to reduce the risk of graft rejection and side effects.

Non-radioactive determination of inosine 5'-monophosphate dehydro-genase (IMPDH) in peripheral mononuclear cells

BACKGROUND

The immunosuppressive activity of mycophenolate mofetil (MMF) is based on the reversible inhibition of inosine 5'-monophosphate dehydrogenase (IMPDH) by mycophenolic acid (MPA). It was the aim of this study to develop a nonradioactive method for specific measurement of IMPDH activity in isolated peripheral mononuclear cells (MNC).

METHODS

The procedure is based on the incubation of lysed MNC with inosine 5'-monophosphate (IMP) followed by direct chromatographic determination of produced xanthosine 5'-monophosphate (XMP). IMPDH activity was measured in MNC of MMF-treated patients and nontreated volunteers.

RESULTS

The within-run (n = 10) and between-run (n = 20) coefficients of variation (CV) for IMPDH activity were < 8% and < 10%, respectively. IMPDH activity in 60 healthy volunteers (19-63 yr) ranged from 4.72 to 32.92 nmol/h/mg protein (mean = 18.39 +/- 6.24). The IC(50) for in vitro inhibition of IMPDH activity was about 2 to 3 microg/L. Application of a single dose of 1 g MMF in dialysis patients resulted in a significant inhibition (by 47-95%; p < 0.05) of IMPDH activity in lysed MNC.

CONCLUSIONS

The proposed assay specifically and reliably measures IMPDH activity in MNC. The procedure is applicable to evaluate pharmacodynamic activity in MMF-treated patients. The observed interindividual variability of IMPDH activity may reflect pharmacodynamic differences in MMF-treated patients.

[An infant with pain and meningeal irritation due to Guillain-Barré syndrome]

In a five-month-old girl, who for a week had cried and displayed a relapse in the motor development, generalised hypotonia and meningism were found. Eventually, the results of the cerebrospinal fluid analysis and electromyography indicated Guillain-Barré syndrome. She was treated with immunoglobulins and made a quick recovery. Guillain-Barré syndrome is an acute or subacute inflammatory demyelinating polyradiculoneuropathy that can occur at any age. In children, the classic symptoms such as a flaccid paralysis and areflexia are not always predominant. Instead, pain is often the most prominent symptom, along with meningism. These symptoms are often insufficiently recognised in practice and as a result of this, delays in the diagnosis of this potentially life-threatening disease often occur.

Single-shot diffusion trace (1)H NMR spectroscopy

Ignoring diffusion anisotropy can severely hamper the quantitative determination of water and metabolite diffusion in complex tissues. The measurement of the trace of the diffusion tensor provides unambiguous and rotationally invariant ADC values, but usually requires three separate experiments. A single-shot technique developed earlier, originally designed for diffusion trace MR imaging (Mori and van Zijl, Magn Reson Med 1995;33:41-52), was improved and adapted for diffusion trace MR spectroscopy. A double spin-echo pulse sequence was incorporated with four pairs of bipolar gradients with specific predetermined relative signs in each of the three orthogonal directions. The combination of gradient directions leads to cancellation of all off-diagonal tensor elements while constructively adding the diagonal elements. Furthermore, the pulse scheme provides complete compensation for cross-terms between static magnetic field gradients and the applied diffusion gradients, while simultaneously avoiding cross-terms with localization gradients. The sequence was tested at 4.7 T in vivo on rat brain for MRI and on rat skeletal muscle and brain for MRS. It is shown that the average ADC as determined from the measurement of the ADCs in the three orthogonal directions is in close agreement with the ADC obtained along the trace of the diffusion tensor in a single acquisition, for both water and metabolite diffusion. The large differences in water and metabolite diffusion coefficients as measured in the individual orthogonal directions illustrate the need for diffusion trace measurements when accurate and rotationally invariant diffusion quantitation is required. The pulse scheme presented here may be applied for such purposes in MRS and MRI studies.

Diffusion NMR spectroscopy

MR offers unique tools for measuring molecular diffusion. This review focuses on the use of diffusion-weighted MR spectroscopy (DW-MRS) to non-invasively quantitate the translational displacement of endogenous metabolites in intact mammalian tissues. Most of the metabolites that are observed by in vivo MRS are predominantly located in the intracellular compartment. DW-MRS is of fundamental interest because it enables one to probe the in situ status of the intracellular space from the diffusion characteristics of the metabolites, while at the same time providing information on the intrinsic diffusion properties of the metabolites themselves. Alternative techniques require the introduction of exogenous probe molecules, which involves invasive procedures, and are also unable to measure molecular diffusion in and throughout intact tissues. The length scale of the process(es) probed by MR is in the micrometer range which is of the same order as the dimensions of many intracellular entities. DW-MRS has been used to estimate the dimensions of the cellular elements that restrict intracellular metabolite diffusion in muscle and nerve tissue. In addition, it has been shown that DW-MRS can provide novel information on the cellular response to pathophysiological changes in relation to a range of disorders, including ischemia and excitotoxicity of the brain and cancer.

Cerebral metabolism in streptozotocin-diabetic rats: an in vivo magnetic resonance spectroscopy study

AIMS/HYPOTHESIS

It is increasingly evident that the brain is another site of diabetic end-organ damage. The pathogenesis has not been fully explained, but seems to involve an interplay between aberrant glucose metabolism and vascular changes. Vascular changes, such as deficits in cerebral blood flow, could compromise cerebral energy metabolism. We therefore examined cerebral metabolism in streptozotocin-diabetic rats in vivo by means of localised 31P and 1H magnetic resonance spectroscopy.

METHODS

Rats were examined 2 weeks and 4 and 8 months after diabetes induction. A non-diabetic group was examined at baseline and after 8 months.

RESULTS

In 31P spectra the phosphocreatine:ATP, phosphocreatine:inorganic phosphate and ATP:inorganic phosphate ratios and intracellular pH in diabetic rats were similar to controls at all time points. In 1H spectra a lactate resonance was detected as frequently in controls as in diabetic rats. Compared with baseline and 8-month controls 1H spectra did, however, show a statistically significant decrease in N-acetylaspartate:total creatine (-14% and -23%) and N-acetylaspartate:choline (-21% and -17%) ratios after 2 weeks and 8 months of diabetes, respectively.

CONCLUSION/INTERPRETATION

No statistically significant alterations in cerebral energy metabolism were observed after up to 8 months of streptozotocin-diabetes. These findings indicate that cerebral blood flow disturbances in diabetic rats do not compromise the energy status of the brain to a level detectable by magnetic resonance spectroscopy. Reductions in N-acetylaspartate levels in the brain of STZ-diabetic rats were shown by 1H spectroscopy, which could present a marker for early metabolic or functional abnormalities in cerebral neurones in diabetes.

In vivo glucose detection by homonuclear spectral editing

A frequency-selective multiple-quantum-coherence spectral editing pulse sequence, Ssel-MQC, was implemented for the detection of the betaH1-glucose resonance at 4.63 ppm in rat brain in vivo. Unwanted signal suppression and glucose coherence transfer pathway selection were performed with magnetic field gradients. To optimize sensitivity, the sequence was executed with surface coil signal reception and adiabatic RF pulse transmission. The glucose editing capabilities of Ssel-MQC were first evaluated in vitro. Ssel-MQC achieved excellent water suppression (suppression factor >10(5)), at the expense of an approximately 60% loss of the glucose signal due to incomplete coherence transfer pathway selection. Next, the sequence was used for in vivo glucose detection in normal rat brain during D-glucose infusion and in the brain of diabetic rats prior to and following insulin infusion.

[Epilepsy, disturbances of behavior and consciousness in presence of normal thyroxine levels: still, consider the thyroid gland]

Three patients, one man aged 51 years, and two women aged 49 and 52 years, had severe fluctuating and progressive neurological and psychiatric symptoms. All three had normal thyroxine levels but elevated thyroid stimulating hormone levels and positive thyroid antibodies. Based on clinical, laboratory, MRI and EEG findings they were eventually diagnosed with Hashimoto's encephalopathy, associated with Hashimoto thyroiditis. Treatment with prednisone in addition to thyroxine suppletion resulted in a remarkable remission of their neuropsychiatric symptoms. The disease is probably under-recognized.

NMR spectroscopic evaluation of cerebral metabolism in hydrocephalus: a review

Cerebral ischemia contributes to cerebral damage in hydrocephalus. Many studies have reported changes in cerebral blood flow and metabolism, supporting this hypothesis. Magnetic resonance spectroscopy (MRS) enables us to investigate cerebral metabolism in a non-invasive and longitudinal manner, thereby providing a promising way of evaluating pathophysiological changes in experimental and clinical hydrocephalus. In this review, the potential of 1H (proton) and 31P (phosphorus) MRS in the assessment of cerebral metabolism will be summarized, and a synopsis of in vitro and in vivo MRS studies in experimental and human hydrocephalus will be presented. Changes in high-energy phosphate metabolism, intracellular pH and lactate production in several MRS studies are presumed to reflect cerebral ischemia. In vivo information on neuronal damage, maturational delay and membrane phospholipid metabolism may also be derived from 1H and 31P MRS data. Technical, methodological and pathophysiological considerations, which are important for a correct interpretation and comparison of different MRS studies, will be discussed. Finally, we will draw some conclusions on the significance of these MRS findings and the applicability of MRS in the diagnosis and evaluation of clinical hydrocephalus.

[Clinical thinking and decision making in practice. A nurse with acute pain between shoulder blades]

A 50-year-old female nurse with an unremarkable medical history experienced acute midthoracic pain, irradiating to the chest and increasing during inspiration. Initial physical examination, laboratory tests, chest X-ray and electrocardiography all were normal. Pulmonary scintigraphy could not be performed in the early stage after admission. The clinical diagnosis of probable pulmonary embolism was made, and anticoagulant therapy was started. The following day, the patient gradually developed a spinal cord syndrome, eventually including paraplegia, bladder dysfunction and an incomplete sensory deficit with an upper level at the 5th thoracic dermatome, predominantly affecting temperature and pain sensation. Magnetic resonance imaging revealed a large anterior spinal epidural haematoma, extending from C7 down to T8. Urgent decompressive laminectomy and subsequent partial evacuation of the haematoma were performed, approximately 24 hours after the onset of neurological signs. No bleeding source was found during operation. The patient made a remarkable postoperative recovery.

Cerebral metabolism in experimental hydrocephalus: an in vivo 1H and 31P magnetic resonance spectroscopy study

OBJECT

Brain damage in patients with hydrocephalus is caused by mechanical forces and cerebral ischemia. The severity and localization of impaired cerebral blood flow and metabolism are still largely unknown. Magnetic resonance (MR) spectroscopy offers the opportunity to investigate cerebral energy metabolism and neuronal damage noninvasively and longitudinally. Previous 1H MR spectroscopy studies have shown an increased lactate resonance that is suggestive of anaerobic glycolysis. The aim of this study was to assess cerebral damage and energy metabolism in kaolin-induced hydrocephalus in adult rats by using in vivo 1H and 31P MR spectroscopy. The presence of lactate was correlated with high-energy phosphate metabolism and intracellular pH. The measurement of relative concentrations of N-acetyl aspartate (NAA), choline (Cho), and total creatine (tCr) served to assess neuronal damage.

METHODS

Hydrocephalus was induced in adult rats by surgical injection of kaolin into the cisterna magna. Magnetic resonance studies, using a 4.7-tesla magnet, were performed longitudinally in hydrocephalic animals at 1 (10 rats), 8 (six rats), and 16 weeks (six rats) thereafter, as well as in eight control animals. To evaluate ventricular size and white matter edema T2-weighted MR imaging was performed. The 1H MR spectra were acquired from a 240-microl voxel, positioned centrally in the brain, followed by localized 31P MR spectroscopy on a two-dimensional column that contained the entire brain but virtually no extracranial muscles. The 1H and 31P MR spectroscopy peak ratios were calculated after fitting the spectra in the time domain, intracellular pH was estimated from the inorganic phosphate (Pi) chemical shift, and T2 relaxation times of 1H metabolites were determined from the signal decay at increasing echo times.

CONCLUSIONS

In hydrocephalic rats, ventricular expansion stabilized after 8 weeks. White matter edema was most pronounced during acute hydrocephalus. Lactate peaks were increased at all time points, without a decrease in phosphocreatine (PCr)/Pi and PCr/adenosine triphosphate (ATP) peak ratios, or pH. Possibly lactate production is restricted to periventricular brain tissue, followed by its accumulation in cerebrospinal fluid, which is supported by the long lactate T2 relaxation time. Alternatively, lactate production may precede impairment of ATP homeostasis. The NAA/Cho and tCr/Cho ratios significantly decreased during the acute and chronic stages of hydrocephalus. These changes were not caused by alterations in metabolite T2 relaxation time. The decreases in the NAA/Cho and tCr/Cho ratios implicate neuronal loss/dysfunction or changes in membrane phospholipid metabolism, as in myelin damage or gliosis. It is suggested that 1H MR spectroscopy can be of additional value in the assessment of energy metabolism and cerebral damage in clinical hydrocephalus.

In vivo 1H MR spectroscopic imaging and diffusion weighted MRI in experimental hydrocephalus

The severity and progression of ventricular enlargement, the occurrence of cerebral edema, and the localization of ischemic metabolic changes were investigated in a rat model of hydrocephalus, using in vivo 1H MR spectroscopic imaging (SI) and diffusion weighted MRI (DW MRI). Hydrocephalic rats were studied 1, 2, 4, and 8 weeks after injection of kaolin into the cisterna magna. Parametric images of the apparent diffusion coefficient (ADC) revealed a varying degree of ventriculomegaly in all rats, with different time courses of ventricular expansion. Extracellular white matter edema was observed during the early stages of hydrocephalus, most extensively in cases of progressive ventriculomegaly. In gray matter regions, ADC values were not changed, compared with controls. In case of fatal hydrocephalus, high lactate levels were observed throughout the whole brain. In all other rats, at all time points after kaolin injection, lactate was detected only in voxels containing cerebrospinal fluid. This suggests accumulation of lactate in the ventricles, and/or an ongoing periventricular production of lactate as a consequence of cerebral ischemia in experimental hydrocephalus.

Cerebral ischemia and white matter edema in experimental hydrocephalus: a combined in vivo MRI and MRS study

T2 and diffusion weighted MRI, as well as 31P and 1H MRS were performed in kaolin-induced hydrocephalic rats. Extracellular white matter edema was detected in the early stages of progressive hydrocephalus. Phosphocreatine (PCr)/inorganic phosphate (Pi) ratios in hydrocephalic animals were decreased compared to controls, and lactate was detected during the acute and chronic stages of hydrocephalus. These MR spectroscopic results are indicative of a compromised energy metabolism and suggest the occurrence of cerebral ischemia in experimental hydrocephalus.

A discriminant function for preeclampsia: case-control study of minor hemoglobins, red cell enzymes, and clinical laboratory values

A case-control study was performed in eight pairs of women to determine whether preeclamptic women developed abnormalities in minor hemoglobins, glycolytic enzymes, or other blood components that might provide insight into the pathophysiology of preeclampsia, or that in combination might be used as a marker for the condition. These variables and standard clinical tests were analyzed as discriminators between preeclamptic and control women. The subjects were matched for age, ethnicity, parity, and gestational age. Blood samples were taken at the time of diagnosis of preeclampsia and at comparable gestational ages for matched normal controls. Variables differing significantly between groups included increases in uric acid (UA), low-density lipoproteins (LDL), phosphoglycerate kinase (PGK), and mean platelet volume (MPV), and decreases in glyceraldehyde phosphate dehydrogenase (G3PD) in preeclamptic women compared to normal controls. Discriminant analysis revealed the following function to separate the groups: 0.7764 (UA) + 0.8086 (PGK) -0.7032 (G3PD) + 0.1399 (LDL) -0.2386 (MPV). A discriminant score of > or = 275 indicated a > or = 90% probability of preeclampsia. The results are consistent with perturbations in red cell glycolysis in preeclampsia. Further prospective studies are warranted to test the efficacy of this discriminant function in predicting preeclampsia.

Stable acetaldehyde adducts: structural characterization of acetaldehyde adducts of human hemoglobin N-terminal beta-globin chain peptides

Acetaldehyde is the first oxidation product of ethanol in vivo. Our earlier work showed that with sufficient acetaldehyde, five of the six possible sites of the peptide pentalysine were modified as a Schiff base (Braun KP, et al: J Biol Chem 270:11263-11266, 1995). However, we were unable to deduce unequivocally which site was unmodified. Lysine residues, as well as the amine terminal valine residues, in hemoglobin have been implicated as target structures for acetaldehyde adducts resulting from ethanol consumption. Hemoglobin adducts of acetaldehyde have been used clinically as a marker of ethanol consumption, but the chemical nature of these adducts remains undefined. As part of our continuing structural characterization of acetaldehyde-protein adduct formation, we studied the peptides Val-His-Leu-Thr-Pro and Val-His-Leu-Thr-Pro-Val-Glu-Lys, from the amine terminus of the beta-globin chain of hemoglobin, in vitro. Both peptides have at least one potential site for adduct formation. In the octapeptide, the N-terminal amine group of Val as well as the epsilon-amine group of the lysine sidechain can potentially be modified by acetaldehyde. We used mass spectrometry, carbon-13 nuclear magnetic resonance, and Raman spectroscopy and characterized stable Schiff base acetaldehyde adducts of these two peptides at both reactive sites. The identification of stable Schiff base adducts with the N-terminal peptides of the beta-chain of hemoglobin as well as with epsilon-amino groups of lysine provides another possible means of monitoring ethanol consumption. The functional implications of these stable Schiff bases remains undefined.

[The neurologic differential diagnosis of unilateral headache and facial pain]

The most frequent and relevant neurologic causes of unilateral headache and facial pain are discussed. Symptomatic headache syndromes, caused by an underlying neurologic disease or structural lesion, are distinguished from idiopathic (essential) pain syndromes, which are characterized by a typical clinical presentation and the absence of a known etiology or pathogenesis.

Validated fluorimetric HPLC analysis of acetaldehyde in hemoglobin fractions separated by cation exchange chromatography: three new peaks associated with acetaldehyde

Stable hemoglobin-acetaldehyde adducts present in hemoglobin fractions separated by polyaspartic acid cation exchange chromatography were quantified by fluorimetric HPLC. The fluorescent species eluted from the HPLC was confirmed by mass spectrometry to be consistent with the expected product from reaction of acetaldehyde, 1,3-cyclohexanedione (CHD), and ammonium ion. Hemolysate (2.2 mM hemoglobin) was incubated in equivalent volumes of either phosphate-buffered saline or 5 mM acetaldehyde at 37 degrees C for 30 min and washed three times with H2O to remove free acetaldehyde and labile adducts before the injection of 14.7 mg hemoglobin onto the cation exchange column. Fluorimetric HPLC analysis of hemolysate samples either with or without in vitro reaction with acetaldehyde revealed that most acetaldehyde resides in the hemoglobin A0 fraction. The reaction with acetaldehyde in vitro resulted in a significant increase in fast-eluting minor hemoglobin species on cation exchange chromatography concomitant with increased acetaldehyde in the HbA1a+b, HbA1c, and HbA1-AcH fractions. We report three new cation exchange chromatographic peaks after reaction with acetaldehyde: HbA1-AcH-3, HbA1c-1, and HbA0-1. Each new peak was found to associate with a significant quantity of CHD-reactive acetaldehyde. These experiments provide additional evidence that stable adducts form between acetaldehyde and hemoglobin and that these adducts occur in multiple hemoglobin species separated by cation exchange chromatography. Further characterization and structural assignment of these species are warranted in view of their potential utility as markers for ethanol intake.

A structural assignment for a stable acetaldehyde-lysine adduct

Acetaldehyde is the first oxidation product of ethanol in vivo. Lysine residues in proteins such as hemoglobin have been implicated as target structures for acetaldehyde adducts resulting from ethanol consumption. Although the presence of both stable and unstable acetaldehyde-hemoglobin adducts has been established, the structural characterization of the adducts has received relatively little attention. As a model for such adduct formation, we studied the peptide pentalysine in vitro. Pentalysine has several potential sites for adduct formation. The amino-terminal amine group as well as the epsilon-amine groups of each lysine side chain can serve as potential sites for modification by acetaldehyde. Mass spectrometry, nuclear magnetic resonance, and Raman spectroscopy were employed to demonstrate that acetaldehyde forms a stable linkage to lysine amine groups via a Schiff base.

Non-invasive ICP monitoring in infants: the Rotterdam Teletransducer revisited

Measurement of intracranial pressure (ICP) is important in patients at risk of raised ICP, as in hydrocephalus. Ideally, it should be non-invasive, thus avoiding the risk of infection and other complications: Such is provided by measurement of ICP through the anterior fontanelle. There are several methods of measuring anterior fontanelle pressure (AFP); those most frequently used are based on the applanation principle. An evaluation of AFP measurement devices resulted in the choice of the Rotterdam Teletransducer (RTT) to be used in our study of children with hydrocephalus. The literature contains little information on the accuracy or validation of the AFP measurements using the RTT. Therefore, the physical qualities of the RTT were reassessed, using a specially developed calibration device. The results of this study demonstrate that membrane temperature does not have any effect on the measured pressure. The thermal stabilization time of the RTT was found to be 3 h after switching on. Insufficient thermal stabilization results in a pressure underestimation of up to 3 mmHg. Furthermore, a maximum inaccuracy of 2.6 mmHg, after calibration and readjustment of the transducer, was calculated. Validation of the equipment was achieved by simultaneous AFP/ICP measurements in hydrocephalic patients showing high correlations (r = 0.96-0.98). The discussion suggests a measurement protocol as a means of increasing the reliability of RTT measurements.

Acetaldehyde-serum protein adducts inhibit interleukin-2 secretion in concanavalin A-stimulated murine splenocytes: a potential common pathway for ethanol-induced immunomodulation

Variable immunobiological changes occur with alcohol consumption. Previous studies have shown that acetaldehyde forms stable adducts with serum proteins, including albumin. These adducts are elevated in persons and animals consuming ethanol. We examined the effect of serum protein-acetaldehyde adducts formed with fetal bovine serum (FBS) on concanavalin A-stimulated murine splenocytes. Interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R) expression were determined as a function of the effect of the acetaldehyde-protein adduct(s). FBS was incubated with acetaldehyde (500, 100, 50, 25, 10, and 0 microM) for 1 hr at 37 degrees C. Excess acetaldehyde was removed by ultrafiltration using a 500 molecular weight cut-off membrane in 3 volumes. Free as well as bound acetaldehyde was quantified using fluorigenic HPLC before and after incubation. Recovered acetaldehyde correlated with the amount added (r2 = 0.996). Splenocytes were cultured for 48 hr in complete medium containing 5% acetaldehyde-treated and 5% untreated FBS with 4 micrograms/ml concanavalin A. Although cell viability was unchanged, acetaldehyde-treated FBS mixed with native FBS decreased IL-2 secretion in a dose-dependent manner. The percentage of cells expressing IL-2R was reduced only at the highest acetaldehyde-FBS dose. Therefore, immunological effects ascribed to ethanol may result in part from the toxic properties of acetaldehyde-protein adducts on IL-2 secretion.

The utility of 2-hydroxypropyl-beta-cyclodextrin as a vehicle for the intracerebral and intrathecal administration of drugs

The substituted glucopyranose ring structure 2-hydroxypropyl-beta-cyclodextrin (CDEX) increases the solubility of molecules by inclusion of the agent in the lipophilic interior of the ring. This property is of particular use for the administration of molecules by the intracerebral (ICV) or intrathecal (IT) routes. In concentrations up to 40% w/v (isotonic), this agent (10 microliters) effect upon nociceptive or motor function after IT injection or on EEG and general behavior after ICV injection in rats. Using 20% CDEX, there is no change in the ED50 as compared to saline on the hot plate (HP) after IT injection of morphine, D-Ala2-D-Leu5 enkephalin or Tyr-Aib-Gly-gPhe-mAib-NH2, (Aib: alpha-aminoisobutyric acid) although there is an increase in their respective durations of effect. Cyclic peptide opioids: Tyr-c[D-A2bu-Gly-D-beta Nal(1)-D-Leu] (A2bu: alpha, gamma-diaminobutyric acid; beta-Nal(1): beta-naphthylalanine(1)) or Tyr-c[DA2bu-Gly-beta Nal(1)-D-Leu] are insoluble in saline but are readily dissolved in CDEX, and display a naloxone-sensitive antinociception following spinal administration. In other studies, saline insoluble capsaicin is administered in 25% dimethylsulfoxide (DMSO) or 20% CDEX (15 microliters; 5 mg/ml) which result in a significant reduction in the spinal levels of substance P and calcitonin gene related peptide and an increase in the HP latency. DMSO alone, but not CDEX alone, reduces the levels of the two peptides. These data emphasize the utility of complexation with CDEX for intracerebral drug delivery and compatibility with brain and spinal tissue.

[Primary aldosteronism]

The syndrome of primary aldosteronism is caused either by an aldosterone-producing adenoma or by idiopathic bilateral adrenal hyperplasia. Hypokalemic hypertension is the leading symptome of the disease. Diagnosis is by the combination of abnormally high and non-suppressible aldosterone values with undetectable or low renin values unresponsive to postural changes or salt restriction. Patients with aldosterone-producing adenoma normally show a fall in plasma aldosterone in response to posture and ACTH-dependent circadian rhythm of aldosterone, whereas bilateral hyperplasia is characterized by postural increases in plasma aldosterone and an ACTH-independent diurnal aldosterone rhythm. These creteria serve to differentiate between adenoma and hyperplasia. An aldosterone-producing adenoma can be localized by veinography, determination of aldosterone concentration in both adrenal veins and by 131I-cholesterol scintigraphy. In our hands the determination of aldosterone in blood from both adrenal veins is the most efficient procedure. In interpreting the results, however, rhythmic and sudden changes in adrenal hormone secretion should be considered. In cases where no adrenal venous blood is obtained, 131I-cholesterol scintigraphy may be used to localize adenoma. In patients with aldosterone-producing adenomas unilateral adrenalectomy should be performed, whereas patients with idiopathic bilateral hyperplasia should receive antihypertensive therapy. As rare instances of primary aldosteronism, a case of aldosterone-producing carcinoma of the adrenal cortex and a case of presumably unilateral adrenal hyperplasia are reported.