Infective acute transverse myelopathy. Report of two cases

Two children with acute transverse myelopathy following adenovirus and Borrelia Burgdorferi infections are presented. The diagnosis stems from the clinical presentation, the determination of specific antibodies in serum and the favorable response to penicillin treatment in the case of neuroborreliosis. Both children made a good recovery. The cerebrospinal fluid examination showed a highly increased myelin basic protein concentration, indicating demyelination.

The spot test is not a reliable screening procedure for mucopolysaccharidoses

To check the reliability of the Ames MPS paper spot test, which is based on the Azure A dye, we sent a series of urine samples to three laboratories where the spot test is part of the metabolic screening for mucopolysaccharidoses. In these laboratories false-negative results ranged between 19% and 35% and false-positive results ranged between 12% and 29% of all samples submitted. In contrast, the quantitative dimethylmethylene blue test (Clin Chem 1989;35:1472-7) detected an increased glycosaminoglycan content in all urine samples from mucopolysaccharidosis patients and gave no false-positive results. In the latter procedure, glycosaminoglycan content is expressed per millimole of creatinine, and age-dependent reference values are used. We conclude that the Ames spot test and other spot tests are unreliable as a screening procedure for mucopolysaccharidoses and should not be used to screen for these diseases.

The spot test is not a reliable screening procedure for mucopolysaccharidoses

To check the reliability of the Ames MPS paper spot test, which is based on the Azure A dye, we sent a series of urine samples to three laboratories where the spot test is part of the metabolic screening for mucopolysaccharidoses. In these laboratories false-negative results ranged between 19% and 35% and false-positive results ranged between 12% and 29% of all samples submitted. In contrast, the quantitative dimethylmethylene blue test (Clin Chem 1989;35:1472-7) detected an increased glycosaminoglycan content in all urine samples from mucopolysaccharidosis patients and gave no false-positive results. In the latter procedure, glycosaminoglycan content is expressed per millimole of creatinine, and age-dependent reference values are used. We conclude that the Ames spot test and other spot tests are unreliable as a screening procedure for mucopolysaccharidoses and should not be used to screen for these diseases.

Effect of various agents on the cytoplasmic calcium concentration in cultured human muscle cells

1. We determined the cytoplasmic Ca2+ concentration ([Ca2+]i) in cultured human muscle cells using the fluorescent indicator Quin-2. 2. The [Ca2+]i was dependent on the external Ca2+ concentration. Acetylcholine in the presence of external Ca2+ caused a transient increase in [Ca2+]i. Inhibition by nifedipine indicated that this response was mediated through activated voltage-operated channels. In nominally Ca2(+)-free buffer acetylcholine did not markedly increase [Ca2+]i. Therefore, the increase in [Ca2+]i as a response to depolarization is mainly due to influx of external Ca2+. 3. Various concentrations of caffeine did not influence the [Ca2+]i. Dantrolene decreased [Ca2+]i, both in the presence and absence of external Ca2+. The reduction probably resulted from an action of dantrolene on the intracellular Ca2+ stores, since dantrolene did not influence 45Ca2+ influx or efflux and caffeine partially counteracted the reduction.

The calcium homeostasis and the membrane potential of cultured muscle cells from patients with myotonic dystrophy

Using the fluorescence indicator, quin2, we compared the cytoplasmic Ca2+ concentration ([Ca2+]i) of cultured myotubes obtained from control subjects and myotonic dystrophy (MyD) patients. In Ca2(+)-free buffer the [Ca2+]i of the cultured MyD muscle cells was not significantly different from that of the control cells. In the presence of 1 mM external Ca2+ the cultured MyD muscle cells showed a significantly higher [Ca2+]i, which was due to the influx of Ca2+ through voltage-operated nifedipine-sensitive Ca2+ channels. In the presence of external Ca2+, MyD myotubes did not respond to acetylcholine, whereas control myotubes showed a transient increase in [Ca2+]i after addition of acetylcholine. This increase was inhibited by the addition of nifedipine. The differences in Ca2(+)-homeostasis between cultured MyD muscle cells and control cells were not due to differences in the resting membrane potential or the inability of the MyD cells to depolarize as a response to acetylcholine. Therefore, cultured MyD muscle cells exhibit altered nifedipine-sensitive voltage-operated channels which are active under conditions in which they are normally present in the inactive state, and which are unable to respond to depolarization caused by acetylcholine.

Vitamin B12 and folate concentrations in serum and cerebrospinal fluid of neurological patients with special reference to multiple sclerosis and dementia

Vitamin B12 and folate concentrations were measured in serum and cerebrospinal fluid (CSF) in 293 neurological patients. Serum and CSF vitamin B12 concentrations showed a positive correlation. In individual patients CSF B12 concentrations varied considerably for a given serum concentration. The median serum vitamin B12 concentration of the Alzheimer's type dementia group was significantly lower compared with that of a control group. Lower median CSF vitamin B12 concentrations were found in groups of patients with multiple sclerosis and Alzheimer's type dementia. Five patients with heterogeneous clinical pictures had unexplained low serum and CSF B12 concentrations without macrocytosis. Two patients had very high serum B12 and low-normal CSF concentrations which could be explained by a blood-brain barrier transport defect. Serum and CSF folate concentrations did not show significant differences between the various groups.

GM2-gangliosidosis. Clinical and biochemical aspects of four cases

We discuss four cases of GM2-gangliosidosis. In one of them the biochemical diagnostic confirmation was difficult. This case revealed striking discrepancies between the results of different methods of enzyme assay. The hexosaminidase A determination based on pH inactivation is not always reliable; assay with natural substrate may be necessary. However, the results with the newly developed substrate 4-MU-GlcNac-6-SO4 are promising and it seems to be a good alternative to the traditional (pH or heat) inactivation procedures. The deficiency can be shown in leukocytes, plasma and fibroblasts with the 6-sulfated substrate. The carrier state seems better reflected in plasma hexosaminidase A than in leukocyte hexaminidase A levels.

Excessive plasma K+ increase after ischemic exercise in myotonic muscular dystrophy

Changes in plasma electrolyte levels upon ischemic forearm exercise were studied in myotonic muscular dystrophy (MyD) patients, disease control groups, and healthy volunteers. Significant differences were observed in the pH and the concentrations of creatine kinase and Na+ before exercise between healthy volunteers and MyD patients. In comparison with healthy volunteers a lower pH and higher concentrations of both CK and Na+ were found in MyD patients. The concentrations of K+, inorganic phosphate, lactate, and ammonia increase upon exercise in all groups. The mean increase in plasma K+ for healthy volunteers amounted to 0.8 mM (= 23%). In MyD patients a significantly higher increase in plasma K+ was found [mean 2.2 mM (= 65%)]. No abnormal release of K+ from muscular tissue was found in the disease control groups. Data on the postexercise increase in the concentration of other muscular constituents such as creatine kinase, inorganic phosphate, or creatine exclude the possibility of a generally increased membrane permeability in MyD. The abnormally high increase of plasma K+ upon muscular exercise seems to be specific for MyD and may be related to the biochemical defect in this disease.

Dimethylmethylene blue-based spectrophotometry of glycosaminoglycans in untreated urine: a rapid screening procedure for mucopolysaccharidoses

Glycosaminoglycans (GAGs) are measured in urine to screen for mucopolysaccharidoses. Other assay procedures are only qualitative (spot tests), can give false-negative results (spot tests, turbidity tests), or are relatively laborious (uronic acid-carbazole test). The present spectrophotometric procedure, based on the color reaction with dimethylmethylene blue (DMB), can be performed directly on untimed urine samples without prior precipitation. Reference values were age dependent. We tested urines of 27 patients with various mucopolysaccharidoses and compared results by three other procedures (cetylpyridinium chloride turbidity tests at pH 4.8 and at pH 7.0, and the uronic acid-carbazole test). In the DMB assay, GAGs were increased in 26 of the 27 patients. The exception was a Morquio A patient, whose activity of the defective enzyme was higher than in classical Morquio patients. Uronic acid, measured in precipitated GAG by the carbazole test, was increased in 23 of the 25 patients so tested. In the turbidity test at pH 7.0, values were increased in 24 of the 27 patients. In contrast, with the citrate-buffered (pH 4.8) turbidity measurement, GAG content was increased in only 19 of the 27 patients. This rapid and easy DMB method is a reliable screening procedure for mucopolysaccharidoses and compares well with procedures used hitherto.

Dimethylmethylene blue-based spectrophotometry of glycosaminoglycans in untreated urine: a rapid screening procedure for mucopolysaccharidoses

Glycosaminoglycans (GAGs) are measured in urine to screen for mucopolysaccharidoses. Other assay procedures are only qualitative (spot tests), can give false-negative results (spot tests, turbidity tests), or are relatively laborious (uronic acid-carbazole test). The present spectrophotometric procedure, based on the color reaction with dimethylmethylene blue (DMB), can be performed directly on untimed urine samples without prior precipitation. Reference values were age dependent. We tested urines of 27 patients with various mucopolysaccharidoses and compared results by three other procedures (cetylpyridinium chloride turbidity tests at pH 4.8 and at pH 7.0, and the uronic acid-carbazole test). In the DMB assay, GAGs were increased in 26 of the 27 patients. The exception was a Morquio A patient, whose activity of the defective enzyme was higher than in classical Morquio patients. Uronic acid, measured in precipitated GAG by the carbazole test, was increased in 23 of the 25 patients so tested. In the turbidity test at pH 7.0, values were increased in 24 of the 27 patients. In contrast, with the citrate-buffered (pH 4.8) turbidity measurement, GAG content was increased in only 19 of the 27 patients. This rapid and easy DMB method is a reliable screening procedure for mucopolysaccharidoses and compares well with procedures used hitherto.

[Sphingomyelinase activity in a patient with Niemann-Pick disease]

In a few months old baby a visceromegaly was found, without other clinical abnormalities. Using an artificial substrate a deficiency of sphingomyelinase could not be demonstrated. Histopathological examination of biopsied liver revealed a lipid storage disease. Using the natural substrate the deficiency of sphingomyelinase could be demonstrated in leucocytes and in cultured fibroblasts.

An immunobioluminescence assay for gamma-gamma enolase activity in human serum and cerebrospinal fluid

A solid phase immunobioluminescence assay for the measurement of gamma-gamma enolase activity in human serum and cerebrospinal fluid is described. The assay combines the specificity of the antiserum with the specificity of measuring enolase activity, thus making the assay highly specific for gamma-gamma enolase. The sensitivity of the method allows determinations in unconcentrated cerebrospinal fluid samples. The new immunobioluminescence assay has been compared with a radioimmunoassay method. The correlation is good both for serum and CSF samples. However, different correlation lines are found for serum and CSF.

Acute transverse myelopathy as the initial manifestation of probable systemic lupus erythematosus in a child

A 10-year-old girl was presented with acute transverse myelopathy. She had three mild relapses within one year. Systemic lupus erythematosus (SLE) was suspected on the basis of positive antinuclear antibodies (ANA), moderately decreased total hemolytic complement, antibodies to histone, immunological abnormalities of kidney and skin biopsy. Symptoms of SLE involving other organs were absent.

The short-term effect of an immunosuppressive treatment on CSF myelin basic protein in chronic progressive multiple sclerosis

CSF levels of myelin basic protein (MBP) and intrathecally produced CSF IgG (de novo IgG) were measured in 11 chronic progressive multiple sclerosis patients with a deteriorating course of the disease for at least 6 months preceding observation and a reference group of 17 neurological patients suffering from disc herniation. In the multiple sclerosis patients, CSF levels were determined just before and once in the period 3 to 10 weeks after the start of an immunosuppressive treatment with cyclophosphamide and prednisone. For multiple sclerosis patients the CSF MBP levels before treatment were significantly higher than for controls. The CSF MBP levels after the treatment were nearly all within the control range. The abnormal high concentration of intrathecally produced CSF IgG (de novo IgG) in multiple sclerosis patients was reduced after treatment. A correlation between CSF MBP and CSF de novo IgG in multiple sclerosis patients could not be demonstrated. If CSF MBP is an indicator of the (activity of) myelin breakdown in the brain, it can be concluded that an intensive immunosuppressive treatment in combination with prednisone has, at least, a short-term, beneficial effect on the amount of demyelinisation and possibly on the disease activity.

Myoadenylate deaminase deficiency: a clinical, genetic, and biochemical study in nine families

The clinical significance of myoadenylate deaminase (MAD) deficiency and its mode of inheritance is still questioned. There were 36 relatives of 9 unrelated MAD deficient patients who were examined with the aid of a standardized ischemic forearm test: 8 new cases of MAD deficiency were detected, 5 of which were confirmed histochemically and biochemically. Obligate heterozygotes showed a normal ammonia production and MAD staining, but the mean activity of the enzyme was significantly less than in a group of controls. The results obtained from the family study strongly suggest an autosomal recessive mode of inheritance. However, only 2 of the 8 newly found MAD deficient individuals complained of exertional myalgia, whereas the remaining 6 were without any symptoms or complaints. This finding casts doubt on the clinical significance of MAD deficiency and the relationship of the deficiency state with exertional myalgia.

CSF concentration and CSF/blood ratio of fuel related components in children after prolonged fasting

In order to obtain information about blood and cerebrospinal fluid (CSF) concentrations, and CSF/blood ratio data of fuel related substrates at the end of a prolonged fast in children, we have selected biochemical data from fasting test procedures in 11 control children aged 3-5 yr, fasted 24 h, and 58 control children aged 6-15 yr, fasted 40 h. There was a good correlation between blood and CSF concentrations for glucose, acetoacetate and beta-hydroxybutyrate. The relation with age and sex has been analyzed only in the older children. CSF and blood values for glucose are positively related with age, and both ketones are negatively related with age. Lactate, pyruvate and alanine concentrations in blood and CSF are not related with age, except for CSF pyruvate. With respect to the CSF/blood ratio for the above mentioned components, only the value for acetoacetate is sex and age related. The calculated median caloric values for the sum of glucose, lactate, pyruvate and ketones in CSF are independent of age at the end of a 40-h fast. The diminished glucose contribution on the CSF caloric homeostasis in younger children is fully compensated by the ketone bodies.

Postsynthetic modification of human enolase isoenzymes

The original form of beta beta enolase (EC 4.2.1.11) in tissue is modified to two more electrophoretically distinct forms when incubated with human serum. The three postsynthetic forms are designated beta beta 3, beta beta 2, and beta beta 1, in order of increasing anodal mobility and increasing modification. Serum and carboxypeptidases A and B all produce identical modifications of beta beta enolase but exhibit very different pH-activity profiles. A purified human serum protein previously named "modifying protein," which is responsible for the modification of creatine kinase-M and alpha-enolase subunits, modifies beta beta enolase and also has a pH-activity profile identical to that for serum. Thus we conclude that the modifying protein is not identical to either carboxypeptidase A or B; it may, however, be an as-yet-undescribed carboxypeptidase. With increased modification, both alpha alpha and beta beta enolase decrease in apparent activation energy; gamma gamma enolase shows no evidence of modification, and its apparent activation energy remains stable. Measurement of activation energy is an easy tool for screening for postsynthetic modifications in an enzyme.

Postsynthetic modification of human enolase isoenzymes

The original form of beta beta enolase (EC 4.2.1.11) in tissue is modified to two more electrophoretically distinct forms when incubated with human serum. The three postsynthetic forms are designated beta beta 3, beta beta 2, and beta beta 1, in order of increasing anodal mobility and increasing modification. Serum and carboxypeptidases A and B all produce identical modifications of beta beta enolase but exhibit very different pH-activity profiles. A purified human serum protein previously named "modifying protein," which is responsible for the modification of creatine kinase-M and alpha-enolase subunits, modifies beta beta enolase and also has a pH-activity profile identical to that for serum. Thus we conclude that the modifying protein is not identical to either carboxypeptidase A or B; it may, however, be an as-yet-undescribed carboxypeptidase. With increased modification, both alpha alpha and beta beta enolase decrease in apparent activation energy; gamma gamma enolase shows no evidence of modification, and its apparent activation energy remains stable. Measurement of activation energy is an easy tool for screening for postsynthetic modifications in an enzyme.

Phenotypic expression in mucopolysaccharidosis VII

beta-glucuronidase deficiency is an extremely rare disorder which is known to have a considerable phenotypic variation. A survey of the clinical findings in 19 previously reported patients with mucopolysaccharidosis VII is presented together with the results of clinical and biochemical studies in two further patients. Because a similar clinical picture is present in a heterozygotic sister it is doubted whether all signs and symptoms can be attributed to the beta-glucuronidase deficiency. The probability of a concomitant disorder is discussed. Diagnosis was made both by demonstration of the deficiency in plasma and leucocytes, and by means of hair root analysis. The phenotypic variation and the fact that increased levels of glycosaminoglycans were not found in the urine of the two patients lead to the suggestion that in certain cases a correct diagnosis may be missed if the beta-glucuronidase activity in plasma and leucocytes is not determined and only routine urine investigation is performed as a screening for a mucopolysaccharidosis. Hair root analysis may be a useful method to measure the beta-glucuronidase activity.

AMP deaminase deficiency: study of the human skeletal muscle purine metabolism during ischaemic isometric exercise

Muscle biopsies were taken from 10 control subjects and five AMP deaminase (AMPD) deficient individuals before and after an ischaemic isometric exercise test and analysed for purine nucleotide, NAD+, creatine phosphate (CP) and lactate content. The decrease of ATP induced by the exercise test was significantly lower in the AMPD deficient patients than in the controls, but the decrease of creatine phosphate and the increase of lactate did not differ. There were no significant differences in the exertional performance level between patients and controls and no evidence was obtained of an increased energy expenditure per unit of performance in AMPD deficiency. The AMPD deficient individuals were equally capable of maintaining a high adenylate energy charge (EC) as the control subjects, which indicates a normal regulation of the balance between ATP consumption and ATP regeneration. ATP, ADP and total adenine nucleotide (TAN) but not AMP, were significantly elevated in the AMPD deficient patients as compared with the controls before as well as after the exercise test. This underlines the role of AMPD activity in the adenine nucleotide catabolism of skeletal muscle.

Intravenous pyruvate loading test in Leigh syndrome

Diagnosis of defective pyruvate metabolism can present difficulties in clinical practice. In search of a diagnostic procedure that can give a clear indication of a disturbance of pyruvate metabolism, we have developed an intravenous pyruvate loading test. The loading test was applied to 9 patients with Leigh syndrome. Results and characteristics are described. The test proved to be a sensitive procedure to detect disturbances in pyruvate oxidation. The intravenous pyruvate loading test can be a useful tool in the diagnosis of mitochondrial (encephalo) myopathies.

Mannosidosis: a study of two patients, presenting clinical heterogeneity

Two unrelated patients suffering from mannosidosis, aged 9 and 33 years, are reported, presenting two extremes in the phenotypic expression of this lysosomal storage disorder. Clinical, radiological, biochemical and therapeutical aspects of the disease are discussed. Our patients support the concept that mannosidosis is not a homogeneous syndrome but manifests wide clinical heterogeneity.

The effects of acute cerebrovascular disease on serum and cerebrospinal fluid parameters

In order to evaluate the effects due to acute cerebrovascular disease on serum and cerebrospinal fluid (CSF) parameters, biochemical data from 312 patients were studied. In serum, CK, LD and alpha 1 protein fraction showed a moderately close relationship to the severity of stroke. In CSF there could not be observed any relation between enzymatic activities (LD, ASAT, CK) and the severity of the disease. The same result was found for CSF protein and the ratio CSF albumin/serum albumin, parameters which are indicative for Blood Brain Barrier (BBB) disturbances. Substances from the intermediate metabolism in the Central Nervous System (CNS) (lactate and pyruvate) were evidently raised in CSF and there was a clear relation between the CSF concentration and the severity of stroke. No indication for IgG immunoglobulin abnormalities in CSF was found. The concentration of neurotransmitter metabolite 5HIAA in CSF was significantly higher in (in)completed stroke than in Transient Ischaemic Attack.

The second wind phenomenon in McArdle's disease

Three patients with McArdle's disease exercised for 2 h at 30% VO2max. During exercise two phases occurred. During the first 15 min they experienced progressive fatigue and weakness of exercised muscles, with a rapid and complete recovery (adaptation phase). Following this, all 3 patients were able to continue exercise without difficulty ('second wind' phase). During the adaptation phase, patients have to cope with their inability to use muscle glycogen as a fuel. Processes occurring during this phase are as follows. An increase in cardiac output. This might be expected to increase muscle blood flow in order to supply exercising muscle with substrates that can substitute for muscle glycogen (free fatty acids (FFA), bloodborne glucose). Changes in the metabolic pathways. These cause a sufficient amount of hexose phosphates to be present to overcome the first 2.5 min of exercise, and FFA and bloodborne glucose to play a major role in energy supply at an earlier stage in exercise than in control subjects. An increase in EMG activity. This is most probably caused by the recruitment of more motor units to compensate for a failure of force generation in the muscle fibres. Central command seems to play an important role in the regulation of cardiovascular processes during the adaptation phase. Despite these compensatory mechanisms, metabolic stress occurs during the adaptation phase. During the 'second wind' phase there are no important differences between the metabolism of exercising muscle of patients with McArdle's disease and that of control subjects.