The value of high-frequency ultrasound in the diagnosis of duchenne muscular dystrophy in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the value of high-frequency ultrasound in the diagnosis of duchenne muscular dystrophy diseases (DMD) in children.</p><p><b>METHODS</b>Eight children with DMD were enrolled as DMD group and 10 healthy children as the control group. The echogenicity of the rectus femoris muscle and the gap between the gastrocnemius and soleus muscles in the two groups were detected by high-frequency ultrasound.</p><p><b>RESULTS</b>Compared with the control group, rectus femoris and gastrocnemius muscles in the DMD group showed increased echogenicity and their muscle fibers were arranged irregularly, and the gap between the gastrocnemius and soleus muscles became wilder (P<0.01).</p><p><b>CONCLUSIONS</b>High-frequency ultrasound is valuable in the diagnosis of DMD.</p>

Diagnostic value of neuronal nitric oxide synthase antibody for clinically suspected Becker muscular dystrophy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Immunohistochemistry using antibodies to dystrophin is the pathological basis for the differential diagnosis of Duchenne and Becker muscular dystrophy (DMD and BMD). In rare cases, however, labelling dystrophin on sarcolemma is equivocal and similar to that observed in controls. This makes the diagnosis of BMD difficult. This study aimed to explore the diagnostic value of neuronal nitric oxide synthase (nNOS) antibody for clinically suspected BMD.</p><p><b>METHODS</b>Immunohistochemical staining was performed on muscle specimens of 5 cases of BMD with positive expression of Dys-C (3 cases had a confirmed diagnosis of BMD, 2 cases were clinically suspected as BMD) by using dystrophin and nNOS antibodies. Normal muscle specimens from the children with fracture were used as controls.</p><p><b>RESULTS</b>Compared with the controls, the expression of Dys-R, Dys-C and Dys-N was markedly reduced and nNOS was not expressed on sarcolemma in the three cases of definitely diagnosed BMD. The two cases of clinically suspected as BMD had a complete absence of sarcolemmal nNOS, even if had a similar expression of dystrophin on sarcolemma to the controls.</p><p><b>CONCLUSIONS</b>nNOS antibody staining can be used for a definite diagnosis in children with clinically suspected BMD who have the almost normal expression of dystrophin.</p>

Clinical application of multiplex ligation-dependent probe amplification for the detection exonic copy number alterations in the Dystrophin gene / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To clarify advantages and disadvantages of using multiplex ligation-dependent probe amplification (MLPA) for detecting exonic deletions and duplications of the Dystrophin gene, and to explore the appropriate management for single-exon abnormality detected by MLPA.</p><p><b>METHODS</b>MLPA were performed to detect exonic copy number changes in 70 Duchenne/Becker muscular dystrophy (DMD/BMD) patients diagnosed by clinical and histological findings. PCR, DNA sequencing and real-time PCR were applied to the samples in which MLPA indicated single-exon deletion or duplication.</p><p><b>RESULTS</b>Of all 70 patients, MLPA detected exonic deletions in 42 (60%), including 12 with single-exon deletion and one with ambiguous single-exon deletion. Exon duplications were found in 7 patients (10%), among which two were single-exon duplication. 21 patients showed normal results (30%). For the 12 patients with single-exon deletion, MLPA results were confirmed by PCR in 11. In one patient, a deletion of two nucleotides (c.4470-4471delAA) was found by sequencing. A novel two-nucleotide deletion (c.4746-4747delCT) was identified in the patient with the ambiguous single-exon deletion. For the two patients showed single-exon duplication, MLPA results were confirmed by real-time PCR.</p><p><b>CONCLUSION</b>MLPA should be the first choice in detecting Dystrophin gene exon deletions and duplications. Single-exon deletion/duplication resulted from MLPA should be further evaluated by other methods.</p>

Genetic tests and clinical re-evaluation of 85 children with suspected spinal muscular atrophy / 中华儿科杂志

<p><b>OBJECTIVE</b>Spinal muscular atrophy (SMA), characterized by degeneration of the anterior horn cells in the spinal cord and symmetric proximal muscle weakness, is the most common autosomal recessive neuromuscular disease in infants and children. In Caucasian population, about 95% of clinically typical patients lack both copies of the telomeric survival motor neuron gene (SMN 1). However, the detection rate of the homozygous absence in Chinese patients is still controversial, which may lead to reduced confidence in the SMA genetic testing in clinical practice. The purpose of the current study was to determine the frequency of homozygous deletions of SMN 1 in Chinese patients, to evaluate the significance of the SMN 1 homozygous deletion assay in clinical applications, and the impact of the clinical re-visit followed by the genetic testing.</p><p><b>METHODS</b>Totally 85 patients initially suspected of SMA were referred for SMA genetic testing. A polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) assay was used to detect the homozygous absence of SMN 1. Clinical re-visit was performed by the pediatric neurology specialists according to the international SMA diagnostic criteria, and histological examinations were carried out when they were necessary.</p><p><b>RESULTS</b>Absence of both copies of SMN 1 exon 7 were found in 57 (67%) of the 85 patients, and 28 patients (33%) had at least one copy. For the 28 patients with negative results, 19 were followed up by the pediatric neurologists. The clinical diagnosis of SMA could be excluded in 15 patients, but retained in the other 4 patients after the clinical re-evaluation and histological examinations. Thus, approximately 95% of the patients with clinically typical SMA in our cohort lacked both copies of SMN 1. Homozygous deletions of SMN 1 were detected in 96% (22/23), 93% (28/30) and 100% (7/7) of the patients with SMA type I, type II and type III, respectively. There was no significant difference in the deletion frequency among the subtypes.</p><p><b>CONCLUSIONS</b>The frequency of homozygous deletions of SMN 1 in this series of Chinese SMA patients was about 95%, which is similar to that reported in Caucasian population. The genetic test of homozygous deletions of SMN 1 should be considered as the first line test for the Chinese patients suspected of SMA. The clinical re-visit and re-evaluation which is essential in clinical diagnosis, genetic counseling and medical management, should be routinely performed after the genetic testing.</p>

Study on metabolism of tetramethylpyrazine in system of rat liver microsomes / 中国中药杂志

<p><b>OBJECTIVE</b>The metabolic character of tetramethylpyrazine (TMPz) in rat liver microsomes was studied in vitro and in vivo to identify which isoforms of cytochrome P450 were responsible for TMPz metabolism in rats, offer the theoretical foundation for the fact that it is rational to use medicine in clinic.</p><p><b>METHOD</b>Set up UV- HPLC method of TMPz, determine concentration of TMPz and its formation in rat plasma and liver microsomes incubation solution, analyze the correlation between TMPz's metabolic eliminate rate and each inducer. Erythromycin( ERY) N-demethylase activity of each sample in rat liver microsomes was measured using N-demethylation reaction of ERY as probe. The correlation between the rate of TMPz metabolite formation and the demethylase activity was analysed. After the SD rats who had been treated with inducer, inhibitor, or untreated, received administration of TMPz in vein, the plasma concentration of TMPz were determined by HPLC. Pharmacokinetic parameters of TMPz were computed and compared.</p><p><b>RESULT</b>The disppearing rate of TMPz in the incubation solutions of the rats liver microsomes, which treated with DEX, were markedly quicker than that of control group (P < 0. 01) , while no obvious difference between P-NF group or PB and control group was observed (P > 0. 05). The activity of ERY-N-demethylase in DEX-induced group was corespondingly enhanced, was much higer than that in control group. The correlation between the rate of TMPz metabolic product formation and the activity of N-demethylase was significant. After using Ket, the CYP3A inhibitor, the metabolism of TMPz could be significantly inhibited the metabolism of TMPz in rat liver microsomes. In vivo, CL( s) were larger than that of the control group,t,/2 were smaller than the control group in DEX group; By contrary, CL(s) was smaller than the control group,t1/2 was larger than the control group in Ket group.</p><p><b>CONCLUSION</b>Results suggest that CYP3A plays a major role in TMPz metabolism in rats, TMPz lie in the possibility of Interaction among the medicines between TMPz and CYP3A inducers or inhibitors when they are used in clinic.</p>