Clinical characterization of dystonia in adult patients with Huntington's disease.

BACKGROUND AND PURPOSE: Huntington's disease (HD) is an autosomal dominant, neurodegenerative movement disorder, typically characterized by chorea. Dystonia is also recognized as part of the HD motor phenotype, although little work detailing its prevalence, distribution, severity and impact on functional capacity has been published to date. METHODS: Patients (>18 years of age) were recruited from the Cardiff (UK) HD clinic, each undergoing a standardized videotaped clinical examination and series of functional assessment questionnaires (Unified Huntington's Disease Rating Scale, Burke-Fahn-Marsden Dystonia Rating Scale and modified version of the Toronto Western Spasmodic Torticollis Rating Scale). The presence and severity of dystonia were scored by four independent neurologists using the Burke-Fahn-Marsden Dystonia Rating Scale and Unified Huntington's Disease Rating Scale. Statistical analysis included Fisher's exact test, Wilcoxon test, anova and calculation of correlation coefficients where appropriate. RESULTS: Forty-eight patients [91% (48/53)] demonstrated evidence of dystonia, with the highest prevalence in the left upper limb (n = 44, 83%), right upper limb most severely affected and eyes least affected. Statistically significant positive correlations (P < 0.05) were observed between dystonia severity and increasing HD disease stage and motor disease duration. Deterioration in functional capacity also correlated with increasing dystonia severity. No significant relationship was observed with age at motor symptom onset or CAG repeat length. CONCLUSIONS: We report a high prevalence of dystonia in adult patients with HD, with worsening dystonia severity with increasing HD disease stage and motor disease duration. The recognition and management of dystonic symptoms in routine clinical practice will aid overall symptomatic treatment and functional improvement.

Assessment of neurologic damage: creatine kinase-BB assay after cardiac arrest.

The assay of cerebrospinal fluid creatine kinase-BB (CK-BB) after cardiac arrest has demonstrated a relationship between CK-BB activity and neurologic recovery; a high concentration of cerebrospinal fluid CK-BB can be associated with lower Glasgow Coma Scale scores, intracranial pressure plateau waves, and histologic brain damage on death. Analysis of cerebrospinal fluid CK-BB is most reliable when it is done within 48 to 72 hours of the arrest. The appearance of serum CK-BB after a cardiac arrest indicates global ischemia, but has not been shown to be a reliable indicator for outcome, because of its rapid inactivation in the body. However, investigations into methods of reactivation of CK-BB show promise in terms of future use of this assay technique.

Efficiency in the diagnosis of acute pancreatitis increased by improved electrophoresis of amylase isoenzyme P3 on cellulose acetate.

Serum from patients who have suffered acute pancreatitis contains P3, an isoenzyme of pancreatic-derived amylase (EC 3.2.1.1). Heretofore, complete resolution of P3 from the major salivary isoenzyme in serum, S1, has not been possible, thus compromising the diagnostic potential of P3 for pancreatitis. I describe an electrophoretic method for the essentially complete resolution of P3 from S1 by including CaCl2, 1 mmol/L, in the Tris barbiturate electrophoresis buffer (25 mmol/L, pH 8.8). I evaluated the clinical utility of the method for 129 consecutive patients suspected of having pancreatitis, by using receiver operating characteristic curve analysis for results for total amylase, P2, and P3 activity. For a true-positive rate of 90% with a prevalence of pancreatitis of 7.8%, the diagnostic efficiency was increased from 82% (total amylase) to 91% (P2) to 98% (P3). Thus, including P3 activity in the diagnostic criteria will eliminate most false-positive results for pancreatitis based on total amylase activity alone, and should decrease the need for expensive radiologic procedures currently required to confirm the presence of pancreatitis. I conclude that P3 can be of significant value in the differential diagnosis of pancreatitis from other syndromes with hyperamylasemia.

Transient creatine kinase-BB activity in serum or plasma after cardiac or respiratory arrest.

We studied the transient appearance of creatine kinase (EC 2.7.3.2) isoenzyme BB, as measured by electrophoresis, in serum or plasma from 19 patients who had just experienced cardiac or respiratory arrest. Creatine kinase BB activity was greatest 0.5 to 3 h after the arrest, with values (measured at 30 degrees C) ranging from 3 to 27 U/L (mean, 7.8 U/L) in 18 patients who were successfully resuscitated. Elimination time for the isoenzyme ranged from 8 to 48 h (mean, 20 h). Elimination t1/2 varied from 4.6 to 16 h for 13 patients from whom adequate serial blood specimens were obtained. We could find no correlation between peak BB activity and eventual case outcome. We attribute this to the near impossibility of drawing a blood specimen exactly when the isoenzyme activity peaks, the instability of creatine kinase BB activity at 37 degrees C, and the fact that nine of these patients died after second or multiple arrests.

Development and clinical evaluation of a microcentrifugal analyzer method for determining creatine kinase MB isoenzyme.

We have adapted to a microcentrifugal analyzer an immunoinhibition assay for measuring the activity of creatine kinase MB by using an inhibitory antibody for the M monomer. The method actually measures half the MB activity, but results are not multiplied by two because atypical isoenzymes of creatine kinase, including BB, IgG-BB, and the isoenzyme derived from mitochondria, are also detected, if they are present. Results correlated well with an electrophoresis method for 36 serum samples. Myocardial infarction was assessed in 175 patients admitted to our coronary-care unit, with respect to sensitivity (100%) and specificity (98%) when a decision point of 100 U/L (30 degrees C) was chosen for total creatine kinase activity (dithiothreitol-activated) and 6 U/L (30 degrees C) for the isoenzyme (by immunoinhibition). Atypical isoenzymes are easily recognized and confirmed by electrophoresis when the MB activity (by immunoinhibition) exceeds 6 U/L and 20% of the total creatine kinase activity.

Creatine kinase isoenzymes in neonate plasma by cellulose acetate electrophoresis: albumin and adenylate kinase artifacts.

Patterns of creatine kinase (CK, EC 2.7.3.2) isoenzymes were studied in apparently healthy one- to 10-day-old neonates, by use of a sensitive fluorescent staining method with Sclavo CK-F/6001 reagent. Mean activities of CK3 (MM, 105 U/L), CK2 (MB, 6.8 U/L), CK1 (BB, 11 U/L), adenylate kinase (EC 2.7.4.3) anodal to CK3, and a fluorescent albumin artifact were found. Pooled plasma from neonates is recommended as a control because it defines the albumin artifact and approximates the activity of CK2 that must be observed after proper staining before a diagnosis of myocardial infarction can be made.

An improved theophylline method by EMIT on the multistat III micro centrifugal analyzer.

We describe several modifications of the Syva EMIT assay for theophylline on the Instrumentation Laboratories Multistat III Micro Centrifugal Analyzer (MCA) designed to improve precision. These modifications include increased sample volume, increased time interval for obtaining the delta optical density, the use of buffer with no detergent to prevent the possibility of premix of reagents, and reversal of the order for loading the reagents. Furthermore, the loading of sample and reagents has been programmed to match the concentrations and sample volume/reagent volume ratios recommended by Syva. Precision analysis of the method yielded coefficient of variation values of less than 10% for controls (n = 52) and standards (n = 69). A cross-correlation study comparing the MCA method and the recommended method on the Gilford 3500 yielded a slope of 0.98, a y intercept of 0.07, and a correlation coefficient of 0.992. The method is precise, fast, and inexpensive, costing ¿63 per patient sample for a full rotor.

Substrate binding properties of converting enzyme using a series of p-nitrophenylalanyl derivatives of angiotensin I.

The binding properties of angiotensin I for the active site of rabbit lung converting enzyme (CE) have been investigated. A series of angiotensin I like substrates, all containing the C-terminal tripeptide, (NO2)Phe-His-Leu, were synthesized by increasing the length of the peptide at the N-terminal end. A total of eight peptides were studied, the largest being [Asn1, (NO2)Phe8]angiotensin I. As determined by thin-layer chromatography, all substrates were hydrolyzed only at the (NO2)Phe-His bond by purified converting enzyme, with the release of the dipeptide, His-Leu. By using an absorbance increase upon hydrolysis, the Michaelis constants and velocity maxima were determined and used to estimate those amino acids in the angiotensin I molecule that contribute significantly to binding to converting enzyme. It was hypothesized that, upon addition or substitution of one or more amino acids to the N-terminal end, a proportional decrease in both KM and Vm is needed in order to conclude that the substrate actually increases its affinity for the enzyme. A test of the proportionality for the variation of KM and Vm was found to be positive for all the substrates, except the N-terminal carbobenzoxy-blocked tripeptide, Z(NO2)Phe-His-Leu. Substitutions near the bond that is hydrolyzed (e.g., proline for the carbobenzoxy group) appear to alter the catalytic properties of CE, while additions far removed from the site of hydrolysis (e.g., the N-terminal tripeptide Asn-Arg-Val) may enhance binding affinity.