Allogeneic stem cell transplantation corrects biochemical derangements in MNGIE

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a multisystemic autosomal recessive disease due to primary thymidine phosphorylase (TP) deficiency. To restore TP activity, we performed reduced intensity allogeneic stem cell transplantations (alloSCTs) in two patients. In the first, alloSCT failed to engraft, but the second achieved mixed donor chimerism, which partially restored buffy coat TP activity and lowered plasma nucleosides. Thus, alloSCT can correct biochemical abnormalities in the blood of patients with MNGIE, but clinical efficacy remains unproven.

Global and region-specific analyses of apparent diffusion coefficient in dentatorubral-pallidoluysian atrophy

BACKGROUND AND PURPOSE

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant spinocerebellar ataxia. Techniques for the quantitative assessment of neurodegenerative lesions remain to be established in this disease. We attempted to quantify global and region-specific neurodegeneration in DRPLA using analysis of apparent diffusion coefficient (ADC) maps.

METHODS

Diffusion-weighted images (b = 1000 s/mm(2)) by echo-planar sequences were obtained with the use of a 1.5T clinical scanner. Whole-brain histogram and region of interest (ROI) analyses of ADC values as well as conventional MR imaging studies were performed in 6 patients with genetically confirmed DRPLA.

RESULTS

Histograms demonstrated significantly higher mean ADC values in the patients than in age- and sex-matched control subjects (P < .01). ROI analysis revealed that the patients had significantly higher ADC values in the cerebellum and globus pallidus, preferentially affected regions (P < .05), but not in the thalamus, the region relatively spared in this disease. ADC values in the white matter were higher only in patients with adult-onset disease. Histogram analyses could more sensitively identify abnormalities than ROI analyses, because the former avoided errors associated with setting ROIs and thus had smaller P values on statistical analysis than the latter.

CONCLUSIONS

Histogram ADC analyses were more sensitive for the detection of neurodegeneration in DRPLA than ROI analyses, whereas ROI analyses revealed regional alterations reflecting the distribution of pathologic changes. Thus, histogram and ROI analyses complement each other and may permit the sensitive, quantitative evaluation of neurodegeneration in DRPLA, especially that involving the globus pallidus showing normal T2 signals.

Immunohistological evaluation of Ki-67, p63, CK19 and p53 expression in oral epithelial dysplasias

BACKGROUND

Oral squamous cell carcinoma develops through a multistep of genetic mutations, and the process can be morphologically recognized as oral epithelial dysplasia. To evaluate the hypothesis that distributional alterations of proliferating and stem cells may be a useful index to estimate the grading and development of epithelial dysplasia, we examined the distribution patterns according to stratified cell layers.

METHODS

Sixty-two oral dysplasia cases according to the histological grades were immunohistologically examined and the nuclear expression of Ki-67 and p63 antigens was counted according to epithelial layers as labeling index.

RESULTS

The Ki-67 labeling index in the basal and suprabasal layers and that of p63 in the basal layer showed a significant difference between low- and high-grade groups of epithelial dysplasia.

CONCLUSION

The architectural alteration of proliferating cell and stem cell distribution in the layers of epithelial dysplasias may provide useful information to evaluate the grading of oral epithelial dysplasias.

Phase 1 study of paclitaxel, cisplatin, and 5-fluorouracil (TCF) in patients with advanced gastric cancer

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Background: Paclitaxel is effective against gastric cancer with serosal involvement and/or peritoneal dissemination. Combination of cisplatin and 5-fluorouracil is also active against advanced gastric cancer. Therefore, we designed a phase I trial of a combination of paclitaxel, cisplatin and 5-fluorouracil (TCF) to explore potential synergistic effect. Methods: Eligible patients had metastatic or unresectable gastric cancer with up to 1 prior chemotherapy regimen. The fixed dose of cisplatin 25 mg/m2 and paclitaxel 80 mg/m2 with escalation dose of 5-fluorouracil from 300 mg/m2 to a maximum of 600 mg/m2 on days 1, 8 and 15 of a 28 day schedule were administered. MTD and anti-tumor activity were evaluated. Results: No grade 3 or 4 toxicities at least possibly related to the treatments resulting in DLT were observed on every dose level. The clinical effects were determined in 3 patients with measurable lesions out of 7 cases. There were 2 partial responses, and disease stabilization was seen in one patient. Conclusions: Combination of paclitaxel, cisplatin and 5-fluorouracil (TCF) is considered to be feasible, well tolerated and active in patients with advanced gastric cancer and warrants further examination in a phase II trial.

No significant financial relationships to disclose.

Dichloroacetate causes toxic neuropathy in MELAS: a randomized, controlled clinical trial

OBJECTIVE

To evaluate the efficacy of dichloroacetate (DCA) in the treatment of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS).

BACKGROUND

High levels of ventricular lactate, the brain spectroscopic signature of MELAS, correlate with more severe neurologic impairment. The authors hypothesized that chronic cerebral lactic acidosis exacerbates neuronal injury in MELAS and therefore, investigated DCA, a potent lactate-lowering agent, as potential treatment for MELAS.

METHODS

The authors conducted a double-blind, placebo-controlled, randomized, 3-year cross-over trial of DCA (25 mg/kg/day) in 30 patients (aged 10 to 60 years) with MELAS and the A3243G mutation. Primary outcome measure was a Global Assessment of Treatment Efficacy (GATE) score based on a health-related event inventory, and on neurologic, neuropsychological, and daily living functioning. Biologic outcome measures included venous, CSF, and 1H MRSI-estimated brain lactate. Blood tests and nerve conduction studies were performed to monitor safety.

RESULTS

During the initial 24-month treatment period, 15 of 15 patients randomized to DCA were taken off study medication, compared to 4 of 15 patients randomized to placebo. Study medication was discontinued in 17 of 19 patients because of onset or worsening of peripheral neuropathy. The clinical trial was terminated early because of peripheral nerve toxicity. The mean GATE score was not significantly different between treatment arms.

CONCLUSION

DCA at 25 mg/kg/day is associated with peripheral nerve toxicity resulting in a high rate of medication discontinuation and early study termination. Under these experimental conditions, the authors were unable to detect any beneficial effect. The findings show that DCA-associated neuropathy overshadows the assessment of any potential benefit in MELAS.

Pre- and post-dialysis quantitative dosage of thymidine in urine and plasma of a MNGIE patient by using HPLC-ESI-MS/MS

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder characterized by severe gastrointestinal dysmotility, cachexia, ptosis, ophthalmoparesis, peripheral neuropathy and leukoencephalopathy. The disease is due to a thymidine phosphorylase defect. This enzyme catalyses the phosphorolysis of thymidine to thymine and deoxyribose 1-phosphate. For this reason, increased levels of thymidine in plasma and urine are found in MNGIE patients. Haemodialysis can reduce circulating plasma thymidine levels and can be beneficial in some MNGIE patients. We developed a fast analytical method based on HPLC-ESI-MS/MS capable of identifying pyrimidine nucleotides (thymine, cytosine, uracil) and nucleosides (thymidine, citidine, uridine) in plasma and urine after direct dilution of the samples without pre-treatment. In the patient studied, we observed a significant reduction of plasmatic and urinary thymidine levels during and after dialysis. However, we noted a progressive reduction of the initial thymidine level after some dialytic trials. This method will be useful not only for thymidine level follow-up during dialysis in MNGIE patients but also for the improvement of the diagnosis or diagnostic suspect in other pyrimidine defects such as dihydropyrimidine dehydrogenase deficiency, dihydropyrimidinase deficiency and ureidopropionase deficiency.

Visualization of hemodynamics in a silicon aneurysm model using time-resolved, 3D, phase-contrast MRI

We performed time-resolved 3D phase-contrast MR imaging by using a 1.5T MR scanner to visualize hemodynamics in a silicon vascular model with a middle cerebral aneurysm. We ran an aqueous solution of glycerol as a flowing fluid with a pulsatile pump. Time-resolved images of 3D streamlines and 2D velocity vector fields clearly demonstrated that the aneurysm had 3D complex vortex flows within it during systolic phase. This technique provided us with time-resolved 3D hemodynamic information about the intracranial aneurysm.

Defects of intergenomic communication: where do we stand?

An expanding number of autosomal diseases has been associated with mitochondrial DNA (mtDNA) depletion and multiple deletions. These disorders have been classified as defects of intergenomic communication because mutations of the nuclear DNA are thought to disrupt the normal cross-talk that regulates the integrity and quantity of mtDNA. In 1989, autosomal dominant progressive external ophthalmoplegia with multiple deletions of mitochondrial DNA was the first of these disorders to be identified. Two years later, mtDNA depletion syndrome was initially reported in infants with severe hepatopathy or myopathy. The causes of these diseases are still unclear, but genetic linkage studies have identified three chromosomal loci for AD-PEO. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), an autosomal recessive disorder associated with both mtDNA depletion and multiple deletions, is now known to be due to loss-of-function mutations in the gene encoding thymidine phosphorylase. Increased plasma thymidine levels in MNGIE patients suggest that imbalanced nucleoside and nucleotide pools in mitochondria may lead to impaired replication of mtDNA. Future research will certainly lead to the identification of additional genetic causes of intergenomic communication defects and will likely provide insight into the normal "dialogue" between the two genomes.

Infantile encephalomyopathy and nephropathy with CoQ10 deficiency: A CoQ10-responsive condition

Coenzyme Q10 (CoQ10) deficiency has been associated with various clinical phenotypes, including an infantile multisystem disorder. The authors report a 33-month-old boy who presented with corticosteroid-resistant nephrotic syndrome in whom progressive encephalomyopathy later developed. CoQ10 was decreased both in muscle and in fibroblasts. Oral CoQ10 improved the neurologic picture but not the renal dysfunction.

Ileosigmoid knot: case report and CT findings

Ileosigmoid knot (ISK) is an unusual clinical entity of small bowel obstruction in which the ileum wraps around the base of the sigmoid colon and forms a pseudo-knot. We present the case of a 75-year-old male in whom ISK was the definitive computed tomographic finding. ISK should be considered in differential diagnosis of patients who present with ileus.

Mosaicism and phenotype in ring chromosome 20 syndrome

Ring chromosome 20 [r(20)] syndrome is a rare chromosomal disorder characterized by epilepsy, mild to moderate mental impairment, and malformation. Patients generally show mosaicism in 1-100% of lymphocytes with r(20). We report here a patient with r(20) syndrome who exhibited mild phenotype with the small ratio of mosaicism (13%) with r(20). Although previous small-scale studies concluded that the mosaicism ratio was unrelated to clinical phenotype, our reassessment of all 57 reported cases has revealed that the ratio is significantly associated with age at seizure onset, intelligence quotient, and malformation, but not with the response of epilepsy to drug treatment. Our results provide important clinical information and prediction for r(20) syndrome.

Coenzyme Q deficiency and cerebellar ataxia associated with an aprataxin mutation

Primary muscle coenzyme Q10 (CoQ10) deficiency is an apparently autosomal recessive condition with heterogeneous clinical presentations. Patients with these disorders improve with CoQ10 supplementation. In a family with ataxia and CoQ10 deficiency, analysis of genome-wide microsatellite markers suggested linkage of the disease to chromosome 9p13 and led to identification of an aprataxin gene (APTX) mutation that causes ataxia oculomotor apraxia (AOA1 [MIM606350]). The authors' observations indicate that CoQ10 deficiency may contribute to the pathogenesis of AOA1.

Thymidine phosphorylase deficiency causes MNGIE: an autosomal recessive mitochondrial disorder

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder caused by mutations in the gene encoding thymidine phosphorylase (TP). The disease is characterized clinically by impaired eye movements, gastrointestinal dysmotility, cachexia, peripheral neuropathy, myopathy, and leukoencephalopathy. Molecular genetic studies of MNGIE patients' tissues have revealed multiple deletions, depletion, and site-specific point mutations of mitochondrial DNA. TP is a cytosolic enzyme required for nucleoside homeostasis. In MNGIE, TP activity is severely reduced and consequently levels of thymidine and deoxyuridine in plasma are dramatically elevated. We have hypothesized that the increased levels of intracellular thymidine and deoxyuridine cause imbalances of mitochondrial nucleotide pools that, in turn, lead to the mtDNA abnormalities. MNGIE was the first molecularly characterized genetic disorder caused by abnormal mitochondrial nucleoside/nucleotide metabolism. Future studies are likely to reveal further insight into this expanding group of diseases.

Increased blood-brain barrier permeability with thymidine phosphorylase deficiency

Mitochondrial neurogastrointestinal encephalomyopathy is an autosomal recessive multisystemic disorder caused by thymidine phosphorylase deficiency. Whereas the pathomechanism of the secondary mitochondrial dysfunction has been extensively studied, that of the leukoencephalopathy has not been elucidated. We hypothesized that the white matter hyperintensities on T2-weighted magnetic resonance images reflect disturbance of blood-brain barrier function. Albumin immunohistochemistry disclosed quantitative (p < 0.01) and qualitative differences between the mitochondrial neurogastrointestinal encephalomyopathy and control brains, indicating that loss of thymidine phosphorylase function impairs the integrity of the blood-brain barrier.

Nuclear envelope alterations in fibroblasts from patients with muscular dystrophy, cardiomyopathy, and partial lipodystrophy carrying lamin A/C gene mutations

Mutations in LMNA, the gene that encodes nuclear lamins A and C, cause up to eight different diseases collectively referred to as "laminopathies." These diseases affect striated muscle, adipose tissue, peripheral nerve, and bone, or cause features of premature aging. We investigated the consequences of LMNA mutations on nuclear architecture in skin fibroblasts from 13 patients with different laminopathies. Western-blotting showed that none of the mutations examined led to a decrease in cellular levels of lamin A or C. Regardless of the disease, we observed honeycomb nuclear structures and nuclear envelope blebs in cells examined by immunofluorescence microscopy. Concentrated foci of lamin A/C in the nucleoplasm were also observed. Only mutations in the head and tail domains of lamins A and C significantly altered the nuclear architecture of patient fibroblasts. These results confirm that mutations in lamins A and C may lead to a weakening of a structural support network in the nuclear envelope in fibroblasts and that nuclear architecture changes depend upon the location of the mutation in different domains of lamin A/C.

Interrelation between HeLa-S3 cell transfection and hemolysis in red blood cell suspension using pulsed ultrasound of various duty cycles

We have studied the in vitro transfection of a plasmid DNA with the lacZ gene to HeLa-S3 cells and hemolysis in a red blood cell (RBC) suspension under pulsed ultrasound with duty cycles gamma of 10, 20 and 30% using a digital sonifier at a frequency of 20 kHz and an intensity of 6.2 W/cm(2) on the surface of a horn tip. Cultured HeLa-S3 cells in suspension were exposed to pulsed ultrasound for an apparent exposure time t' from 0 to 60 s. HeLa-S3 viability decreased as a single exponential function of the total exposure time t = gammat' with a common time constant tau = 3.8 s for three duty cycles. Transfection was evaluated by counting the number of beta-galactosidase(beta-Gal)-positive cells relative to the total number of cells. Pulsed ultrasound provided an enhanced transfer of the beta-Gal plasmid to HeLa-S3 cells, 3.4-fold as compared with that in the case of the control. The optimal transfection efficiencies were 0.75, 0.80 and 0.74% near t = tau with gamma = 10, 20 and 30%, respectively. The number ratio of beta-Gal-positive cells to the surviving cells after exposure increased with t' according to a modified logistic equation. The degree of hemolysis also increased exponentially with t' at a time constant tau' = tau(0)/gamma for the RBC suspension in physiological saline at a hematocrit concentration of 0.5% with tau(0) = 0.9 s. Thus the total exposure time for the optimal transfection efficiency was tau, that is, nearly four times of tau(0). Hemolysis in the RBC suspension may be a useful model for determining optimal transfection by pulsed ultrasound of various duty cycles.

Cerebral lactic acidosis correlates with neurological impairment in MELAS

OBJECTIVE

To evaluate the role of chronic cerebral lactic acidosis in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS).

METHODS

The authors studied 91 individuals from 34 families with MELAS and the A3243G point mutation and 15 individuals from two families with myoclonus epilepsy and ragged red fibers (MERRF) and the A8344G mutation. Subjects were divided into four groups. Paternal relatives were studied as controls (Group 1). The maternally related subjects were divided clinically into three groups: asymptomatic (no clinical evidence of neurologic disease) (Group 2), oligosymptomatic (neurologic symptoms but without the full clinical picture of MELAS or MERRF) (Group 3), and symptomatic (fulfilling MELAS or MERRF criteria) (Group 4). The authors performed a standardized neurologic examination, neuropsychological testing, MRS, and leukocyte DNA analysis in all subjects.

RESULTS

The symptomatic and oligosymptomatic MELAS subjects had significantly higher ventricular lactate than the other groups. There was a significant correlation between degree of neuropsychological and neurologic impairment and cerebral lactic acidosis as estimated by ventricular MRS lactate levels.

CONCLUSIONS

High levels of ventricular lactate, the brain spectroscopic signature of MELAS, are associated with more severe neurologic impairment.

Application of artificial neural network modelling to identify severely ill patients whose aminoglycoside concentrations are likely to fall below therapeutic concentrations

OBJECTIVE

Identification of ICU patients whose concentrations are likely to fall below therapeutic concentrations using artificial neural network (ANN) modelling and individual patient physiologic data.

METHOD

Data on indicators of disease severity and some physiologic data were collected from 89 ICU patients who received arbekacin (ABK) and 61 who received amikacin (AMK). Three-layer ANN modelling and multivariate logistic regression analysis were used to predict the plasma concentrations of the aminoglycosides (ABK and AMK) in the severely ill patients.

RESULTS

Predictive performance analysis showed that the sensitivity and specificity of ANN modelling was superior to multivariate logistic regression analysis. For accurate modelling, a predictable range should be inferred from the data structure before the analysis. Restriction of the predictable region, based on the data structure, increased predictive performance.

CONCLUSION

ANN analysis was superior to multivariate logistic regression analysis in predicting which patients would have plasma concentrations lower than the minimum therapeutic concentration. To improve predictive performance, the predictable range should be inferred from the data structure before prediction. When applying ANN modelling in clinical settings, the predictive performance and predictable region should be investigated in detail to avoid the risk of harm to severely ill patients.

MNGIE with lack of skeletal muscle involvement and a novel TP splice site mutation

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive multisystem disorder caused by thymidine phosphorylase (TP) deficiency, resulting in severe gastrointestinal dysmotility and skeletal muscle abnormalities. A patient is reported with a classical MNGIE clinical presentation but without skeletal muscle involvement at morphological, enzymatic, or mitochondrial DNA level, though gastrointestinal myopathy was present. MNGIE was diagnosed by markedly raised plasma thymidine and reduced thymidine phosphorylase activity. Molecular genetic analysis showed a homozygous novel splice site mutation in TP. On immunohistochemical studies there was marked TP expression in the CNS, in contrast to what has been observed in rodents. It is important to examine the most significantly affected tissue and to measure TP activity and plasma thymidine in order to arrive at an accurate diagnosis in this condition.

A novel autosomal dominant limb-girdle muscular dystrophy (LGMD 1F) maps to 7q32.1-32.2

In 2001, the authors described the clinical features of a genetically distinct autosomal dominant limb-girdle muscular dystrophy (LGMD; LGMD 1F). Using a genome-wide screen with more than 400 microsatellite markers, the authors identified a novel LGMD disease locus at chromosome 7q32.1-32.2. Within this chromosomal region, filamin C, a gene encoding actin binding protein highly expressed in muscle, was an obvious candidate gene; however, the authors did not detect any defects in filamin C or its protein product.