Muscle adenylate kinase in Duchenne muscular dystrophy.

On the basis of electrophoretic and enzyme inhibition studies it was postulated that an aberrant adenylate kinase occurs in muscle and serum of patients with Duchenne muscular dystrophy (Schirmer, R.H. and Thuma, E. (1972) Biochim. Biophys. Acta 268, 92-97; Hamada, M. et al. (1981) Biochim. Biophys. Acta 660, 227-237; Hamada et al. (1985) J. Biol. Chem. 260, 11595-11602). On the basis of the following results we conclude that Duchenne muscular dystrophy patients do not possess an unusual adenylate kinase isoenzyme. In muscle biopsies from five Duchenne patients, the electrophoretic mobility of adenylate kinase and the inhibition of the enzyme by P1, P5-di(adenosine-5')pentaphosphate (Ap5A) was normal. Because of the high SH-group content of the extracts from Duchenne muscle, high concentrations of Ellman's reagent were needed to inhibit adenylate kinase activity in these samples. In Duchenne plasma the adenylate kinase activity was elevated. Like in muscle specimens, the DTNB inhibition curves were shifted to higher reagent concentrations; this was due to a high SH-group content of Duchenne plasma when compared with normal plasma. With respect to inhibition by Ap5A and electrophoretic mobility, Duchenne adenylate kinase in Duchenne plasma behaved like normal muscle adenylate kinase in normal plasma. It was noted that normal muscle adenylate kinase changes its electrophoretic behaviour when mixed with normal or Duchenne plasma. This finding had been considered previously as evidence for the presence of an aberrant adenylate kinase in Duchenne plasma.

Glycosyl-phosphatidylinositols of Trypanosoma congolense: two common precursors but a new protein-anchor.

The parasitic protozoan Trypanosoma congolense exhibits a dense surface coat which is pivotal for immunoevasion of the parasite. This dense surface coat is made of a single protein species, the variant surface glycoprotein, which is present in a high copy number. The protein is anchored to the plasma membrane by a glycosyl-phosphatidylinositol membrane anchor. A detailed study of the structure of T. congolense strain 423 (clone BENat 1.3) variant surface glycoprotein glycosyl-phosphatidylinositol membrane anchor was performed. Radioactively labelled core-glycan prepared by dephosphorylation, deamination and reduction was analysed by high-pH anion-exchange chromatography, size-exclusion and lectin affinity chromatography. Additionally the glycosyl-phosphatidylinositol membrane anchor core-glycan was purified from a bulk preparation of variant surface glycoprotein and subjected to mass spectrometry and methylation analysis. Using these methods we could identify a novel galactose-beta 1,6-N-acetyl-glucosamine-beta 1,4-branch modifying the mannose adjacent to the glucosamine of the mannose-alpha 1,2-mannose-alpha 1,6-mannose-alpha 1,4-glucosamine core-glycan of the variant surface glycoprotein glycosyl-phosphatidylinositol membrane anchor. Furthermore the biosynthetic pathway leading to this novel structure was investigated. Two putative glycosyl-phosphatidylinositol anchor precursors were identified having structures identical to the previously characterized Trypanosoma brucei brucei glycolipids P2 and P3 (also designated glycolipid A and C) consistent with a trimannosyl core and a dimyristoyl-glycerol. Both glycosyl-phosphatidylinositol anchor precursors of T. congolense do not possess the side-branch modification found on the mature protein membrane anchor, implying that the sugar side-chain is added to the anchor during its passage through the Golgi-apparatus.

2-Amino-6-arylsulfonylbenzonitriles as non-nucleoside reverse transcriptase inhibitors of HIV-1.

A series of 2-amino-5-arylthiobenzonitriles (1) was found to be active against HIV-1. Structural modifications led to the sulfoxides (2) and sulfones (3). The sulfoxides generally showed antiviral activity against HIV-1 similar to that of 1. The sulfones, however, were the most potent series of analogues, a number having activity against HIV-1 in the nanomolar range. Structural-activity relationship (SAR) studies suggested that a meta substituent, particularly a meta methyl substituent, invariably increased antiviral activities. However, optimal antiviral activities were manifested by compounds where both meta groups in the arylsulfonyl moiety were substituted and one of the substituents was a methyl group. Such a disubstitution led to compounds 3v, 3w, 3x, and 3y having IC50 values against HIV-1 in the low nanomolar range. When gauged for their broad-spectrum antiviral activity against key non-nucleoside reverse transcriptase inhibitor (NNRTI) related mutants, all the di-meta-substituted sulfones 3u-z and the 2-naphthyl analogue 3ee generally showed single-digit nanomolar activity against the V106A and P236L strains and submicromolar to low nanomolar activity against strains E138K, V108I, and Y188C. However, they showed a lack of activity against the K103N and Y181C mutant viruses. The elucidation of the X-ray crystal structure of the complex of 3v (739W94) in HIV-1 reverse transcriptase showed an overlap in the binding domain when compared with the complex of nevirapine in HIV-1 reverse transcriptase. The X-ray structure allowed for the rationalization of SAR data and potencies of the compounds against the mutants.

Platelet-activating factor analogs. II. Synthesis of the 1-O-(4-decyloxymethylphenyl)- and 1-O-(4-decyloxyphenylmethyl) analogs.

1-O-(4-Decyloxymethylphenyl)- and 1-O-(4-decyloxyphenylmethyl)-2-O-acetyl-glycero-3-phosphorylcholin e were synthesized from 2,2-dimethyl-1,3-dioxolane-4-methanol. The utility of a 2-O-tetrahydropyranyl ether as a protecting group and its facile removal in the presence of a 3-phosphorylcholine is illustrated.

Acetazolamide treatment for infantile central sleep apnea.

Central sleep apnea is a common respiratory pattern in healthy neonates. Nevertheless, frequent central sleep apnea associated with drops in oxygen saturation may contribute to infantile morbidity. Recently, low-dose acetazolamide was shown to reduce symptomatic central sleep apnea in adults. We treated 12 infants, median conceptional age 42 weeks (range, 40-44 weeks), with central sleep apnea. In all cases, the central apnea index was >40/h total sleeping time (apnea > or = 3 sec). The cumulative duration of drops in oxygen saturation below 90% was more than 3 min/h total sleeping time. All individuals received acetazolamide 7 mg/kg/day (orally, divided in three doses) for 11 weeks. Polysomnography was begun 10 hours before the first dose and continued for 10 hours after the third dose. Polysomnography was repeated after 6 weeks of treatment and 1 week after acetazolamide therapy was discontinued. Comparison of the respiratory patterns before and after treatment (10-hour recording after the third dose) showed a decrease in the median central apnea index from 74/h (range, 42-152/h) to 13/h (range, 6-49/h). The median of the cumulative duration of drops in oxygen saturation below 90% decreased from 3.6 min/h (range, 3.1-9.2 min/h) to 0.07 min/h (range, 0-0.5 min/h). Basal oxygen saturation increased from 95 (92-97%) to 98% (96-99%). This improvement was maintained in the final polysomnography (12 weeks after therapy was begun and 1 week after completion of the 11-week course). No adverse effects were noted. We conclude that low-dose acetazolamide treatment may be useful for the treatment of central infantile sleep apnea associated with hypoxemia.

Ischemic stroke and migraine in childhood: coincidence or causal relation?

Although migraine is an accepted cause of cerebral infarction in adults, this association is less well recognized in children. We present two children with migraine and cerebral infarction, which we regard as migrainous stroke, though neither patient fulfills all criteria of the International Headache Society for the diagnosis of migrainous infarction. Review of the literature concerning examples of migraine-associated stroke in childhood suggests that these criteria are too restrictive to comprise the majority of migrainous strokes, especially in this age group.

Dystrophinopathies.

The discovery of the subsarcolemmal muscle fiber protein dystrophin has, to a certain extent, replaced former nosological terms of Duchenne (DMD) and Becker (BMD) muscular dystrophies by the term dystrophinopathies. The immunohistochemical and Western blot analysis of dystrophin has not only enlarged the clinical spectrum of dystrophinopathies, but has also made carrier detection of DMD more reliable, particularly in manifesting carriers without family history. Moreover, prenatal muscle biopsy, under selected circumstances, can show presence or absence of dystrophin, ie, in the latter case an affected male fetus. Molecular genetics have provided a wealth of genetic details in the dystrophinopathies, but therapy has not yet succeeded to a similar extent, on the contrary, myoblast transplantation has not resulted in any clinical improvement.

Idiopathic de Toni-Debré-Fanconi syndrome with absence of proximal tubular brush border.

In a girl with idiopathic de Toni-Debré-Fanconi syndrome associated with psychomotor retardation, severe renal tubular dysfunction was observed from the first day of life. At the age of 21/2 and 4 years the glomerular filtration rate (GFR) was only 60 ml/min/1.73 m2. No tubular transport of glucose, phosphate, paraaminohippurate and amino acids could be demonstrated. The tubular handling of uric acid, potassium and calcium, was also disturbed. Renal net acid excretion was zero at a plasma bicarbonate level of 14 mmol/l. Urinary osmolality ranged between 88 and 680 mosmol/kg. During hypotonic saline diuresis GFR decreased further; a GFR of 19 ml/min/1.73 m2 was accompanied by a fractional distal sodium delivery of 96.5% and a fractional free water clearance of 73%. In a renal biopsy specimen the proximal tubular cells showed variations in height with dedifferentiation and a widespread absence of brush border on electron microscopy. This formerly undescribed tubulopathy offers a unique chance to investigate glomerulo-tubular balance, adaptive mechanisms of distal tubular transport and renal metabolism under conditions where an apparently unchanged ultrafiltrate is offered by the proximal tubule to the loop of Henle and to a primarily intact distal tubule.

Deflazacort vs. prednisone in Duchenne muscular dystrophy: trends of an ongoing study.

Several studies have demonstrated the slowing effect of corticosteroids on the decline of muscle strength in Duchenne muscular dystrophy (DMD). Deflazacort (DFC) is supposed to have fewer side effects than prednisone (PRED). An ongoing double blind multicenter study is comparing the effects and side effects of deflazacort (0.9 mg/kg/day) and prednisone (0.75 mg/kg/day) in DMD. This interim report includes data for 67 boys between age 5 years and loss of ambulation. Besides the common clinical and laboratory data for chronic corticoid treatment, motor performance has been tested. Interim results, 3-15 months after starting the medication, show some scattering but no grouping of data for all the functions tested: timed motor functions, sum of the strength of 20 muscles according to a 10-point scale on manual testing, weight gain, osteocalcin and alkaline phosphatase. Only the changes in CK activity after 3 months medication might reflect two equal groups without any correlation with the initial activity or with other parameters. On average, there was no clear-cut loss of muscle strength or performance. Except for in 4 patients, who were excluded due to unacceptable weight gain and/or loss of ambulation, there were no side effects considered to be serious. The results suggest that (i) DFC and PRED in equal anti-inflammatory dosage are similarly or equally efficient in slowing down the decline of muscle strength in DMD; (ii) benefits outweigh the side effects. This allows the study to continue as designed.

Identification of infants at risk for infantile spasms by neonatal polygraphy.

Reevaluation of neonatal EEGs and polygraphic tracings of 40 infants with infantile spasms and/or hypsarrhythmia resulted in the constitution of a compound score for the identification of infants at risk for infantile spasms by neonatal EEG. The score comprises 8 distinct items: 2 concern behavioral characteristics, 6 abnormality of EEG background activity and paroxysmal events. A tracing registered at conceptional age 36 to 44 weeks (eventually up to 50 weeks) presenting at least 4 of these 8 items is scored positive for the risk of evolving hypsarrhythmia. In a prospective study the polygraphic tracings of 941 newborn infants were evaluated for risk: 18 infants suffering from perinatal distress and 7 newborns with malformations of the brain were scored positive and all 25 developed infantile spasms and/or hypsarrhythmia. One infant with later infantile spasms was missed by the scoring system. None of the remaining infants scored negative manifested infantile spasms. Thus, correct positive prognostication was 100% and false negative 0.1%. By conventional EEG 5 out of 8 patients with infantile spasms were correctly predicted. The high validity of the risk-score based on polygraphic tracing between conceptional age 36 to 44 weeks may allow pre-onset treatment preventing secondary mental deterioration due to hypsarrhythmia and infantile spasms.

Prenatal diagnosis of infantile neuronal ceroid-lipofuscinosis: a combined electron microscopic and molecular genetic approach.

Based on two unrelated index patients afflicted with INCL, fetal chorion tissues were studied from subsequent pregnancies of the two respective mothers resulting in the prenatal diagnosis of INCL in two of the three pregnancies. Documentation of INCL was based on electron microscopy and DNA studies of the biopsied chorion tissue, later confirmed in the two affected fetuses after termination of their pregnancies by demonstrating INCL-specific lipopigments in post-mortem tissues, in the liver of both aborted fetuses and, additionally, in spleen and skeletal muscle of one of the affected fetuses. The autolysis of the aborted tissues, however, precluded a systematic documentation of all affected cell types and tissues. Thus, prenatal diagnosis of INCL is feasible and reliable for both Finnish and non-Finnish families.

Basilar artery occlusion and the dense artery sign in the newborn.

A child with basilar artery occlusion in the neonatal period is reported. The occlusion was documented by unenhanced computed tomography performed in the neonatal period demonstrating a "dense" artery at the tip of the basilar artery. The pattern of cerebral damage on MRI scan at 10 years of age confirmed the site of the vascular occlusion. The evidence suggests that embolization was the operating pathogenic mechanism of cerebral vascular occlusion. Neonatal arterial thrombosis involving the carotid circulation has been well documented and may be due to many pathological factors including direct trauma to the carotid artery and embolization from remote sites. Thrombosis of the vertebral artery in the neonate is only rarely reported and only in association with significant cervical trauma. A second child with a similar pattern of cerebral injury demonstrated on neuroimaging is described suggesting that this event may be more common than recognized. The clinical features of basilar artery occlusion as seen in the adult are not apparent in the neonate. Recognition of the neuroimaging characteristics seen in this condition may help to provide the clinician with a reasonable pathogenetic explanation for unexplained cerebral injury.

[Cataplexy in type C Niemann-Pick disease]. / Kataplexie bei Morbus Niemann-Pick Typ C.

Cataplexy usually occurs as a part of the tetrad of clinical phenomena of idiopathic narcolepsy. Symptomatic cases are rare. A 4 years old girl from consangineous parents had recurrent loss of muscle tone and fell to the ground, when she laughed. The EEG was normal. Prolonged neonatal jaundice with cholestasis, hepatosplenomegaly, mental regression, supranuclear ophthalmoplegia, and foam cells led to the diagnosis of Niemann-Pick disease type C with symptomatic cataplexy. Symptomatic forms of the narcolepsy-cataplexy complex should be considered, when there is an early onset before puberty, cataplectic attacks predominate the narcoleptic attacks, and when additional neurological symptoms occur. Symptomatic cataplexy occurs in Niemann-Pick disease type C. It is considered to be the result of lesions of the pontine reticular formation.

[Familial paroxysmal choreoathetosis. Clinical course, L-dopa-effect (author's transl)]. / Paroxysmale familiäre Choreoathetose. Verlaufsbeobachtung, L-dopa-Effekt.

The clinical course of two boys with familial paroxysmal choreoathetosis was traced. As far as the medical history could be retrieved, their family has been affected by this disease for three generations. Except for this disorder, the patients' development and psychophysical state are unremarkable. Both boys responded well but at times incompletely to anticonvulsants. Therefore L-Dopa was introduced to the therapeutic regime of the younger, more severely affected boy. L-Dopa caused an appreciable decline of the frequency of the paroxysms.

Neuromuscular reaction to paired stimuli.

A modification of the twin pulse method is described, by which the nerve tested is stimulated at one proximal site percutaneously and the neuromuscular response to it is derived from a dependent muscle. An electronic subtraction procedure provides separation of the conditioned muscle action potential for measurement by means of a microcomputer. Several parameters were determined in the conditioned action potential and compared to the same criteria in an unconditioned single action potential. Changes of the conditioned action potential were measured at fixed stimulus intervals between 2 and 6 msec. Preliminary normal ranges interindividually and intraindividually were established. Their dependency on skin surface temperature was determined. In polyradiculoneuropathy, the data for motor nerve conduction velocity were characteristically pathologic, and neuromuscular reaction to paired stimuli data deviated minimally from normal. In vincristine neuropathy, motor nerve conduction velocity was normal, but neuromuscular reaction to paired stimuli data fell outside the normal range early in the clinical course. Since polyradiculoneuropathy is a primary demyelinating and remyelinating process and vincristine neuropathy is an example of axonal degeneration, neuromuscular reaction to paired stimuli can facilitate the differential diagnosis in polyneuropathy. Furthermore, this method seems apt to quantify axonal degeneration. In a mixed form of polyneuropathy, peroneal muscular atrophy, motor nerve conduction velocity, as well as neuromuscular reaction to paired stimuli, were abnormal, the latter resulting in abnormally high relative amplitudes. In muscle disorders such as Duchenne muscular dystrophy, neuromuscular reaction to paired stimuli data was abnormal, contrasting experiments using double stimulation of the diseased muscle itself.

Neonatal respiratory insufficiency due to centronuclear myopathy.

Two neonates showing generalized hypotonia, weakness of limbs, trunk, and oral musculature died because of muscular respiratory distress. The diagnosis of centronuclear (or myotubular) myopathy was established by histological and histochemical techniques. The genetic situation and routine laboratory data including electromyography were compared with similar cases in the literature; findings were inconclusive with respect to this diagnosis. These results indicate the need for a muscle biopsy and the use of histochemical stainings and/or electronmicroscopical investigation for a proper diagnosis in hypotonic newborns under respiratory distress after exclusion of etiologies other than neuromuscular diseases. Still the diagnosis of centronuclear myopathy in a neonate does not allow a precise prognosis. Increased awareness of this disorder and adequate diagnostic workup is needed in order to extend our understanding and to clarify the prognosis.

[Progressive Duchenne muscular dystrophy: general practice aspects of diagnostic assessment]. / Progressive Muskeldystrophie Duchenne: Praxis der Diagnosefindung.

The analysis of 57 cases of Duchenne muscular dystrophy (DMD) from W.-Germany outlined an average delay in motor development with an extended period of time between learning to stand and to walk. 33 patients could not walk when they were 16 months old. At the age of 27 months people without medical training generally noticed first symptoms. Unexpectedly often quantitative deficiencies in movements became evident. On average 26 months passed until DMD was diagnosed. To improve the situation, the authors propose a selective screening of boys who are not able to walk without help when they are 16 months old (90th percentile for healthy children).

Aplasia of the retinal vessels combined with optic nerve hypoplasia, neonatal epileptic seizures, and lactic acidosis due to mitochondrial complex I deficiency.

A newborn male with mitochondrial complex I deficiency suffered from neonatal epileptic seizures, which later developed into infantile spasms. The infant was blind due to aplasia of the retinal vessels and hypoplasia of the optic nerve. There was congenital lactic acidosis, which persisted in later life. The boy was microcephalic and retarded. Muscular hypotonia later shifted to spasticity. Succinic acid was increased in urine. We assume that the aplasia of the retinal vessels is due to damage of the retinal ganglion cells caused by the mitochondrial disease in the first 3 to 4 months of pregnancy.