Predictors of type 2 diabetes relapse after Roux-en-Y Gastric Bypass: A ten-year follow-up study.

AIMS: To assess the impact of bariatric surgery on remission and relapse of type 2 diabetes mellitus (T2DM) at 10 years of follow-up and analyze predictive factors. MATERIALS AND METHODS: Eighty-eight obese subjects undergoing Roux-en-Y gastric bypass (RYGB) and 25 subjects assigned to medical therapy (MT) were evaluated every year for 10 years. T2DM remission was defined by the American Diabetes Association criteria. RESULTS: Body mass index (BMI), fasting glucose, and haemoglobin A1c (HbA1c) improved more markedly in RYGB than MT patients throughout the 10-year period. Post-surgery remission rates were 74% and 53% at 1 and 10 years, respectively, while remission did not occur in MT patients. One-year post-surgery, BMI decreased more in subjects with remission than in those without, but no further decrease was observed thereafter. By partial-least-squares analysis, T2DM duration, baseline HbA1c, and ensuing insulin therapy were the strongest predictors of remission. Remission was achieved at one year in 91% of patients with T2DM duration < 4 years, and 79% of them remained in remission at 10 years. On the contrary only 42% of patients with T2DM duration ≥ 4 years achieved remission, which was maintained only in 6% at the end of 10 years. By survival analysis, patients with T2DM duration < 4 years had higher remission rates than those with duration ≥ 4 years (hazards ratio (HR) 3.1 [95%CI 1.8-5.7]). Relapse did not occur before two years post-surgery and was much less frequent in patients with < 4- vs ≥ 4-year duration (HR 11.8 [4.9-29.4]). CONCLUSIONS: Short T2DM duration and good glycemic control before RYGB surgery were the best requisites for a long-lasting T2DM remission, whereas weight loss had no impact on the long-term relapse of T2DM.

Novel drug delivery systems for natural extracts: The case study of Vitis Vinifera extract-SiO2 nanocomposites.

Ball Milling technique has been used to prepare for the first time Vitis Vinifera extract-silica nanocomposites (VV-SiO2 NCs), which combine the pharmacological effects of the extract with the effectiveness of silica as drug delivery system and active component in the treatment of wound healing. Different contents (1.0, 9.0 and 33.0 wt%) of Vitis Vinifera ethanolic extract were loaded into the silica matrix by grinding the extract with fumed silica using a planetary mill apparatus. The effect of the starting mixture composition and milling time on the final products was examined. The efficiency of the milling process was studied by X-ray Powder Diffraction, Nuclear Magnetic Resonance, and Infrared Spectroscopy, indicating that the natural extract was not affected by the increasing of the milling time. The successful loading of the extract was demonstrated by Nitrogen adsorption/desorption measurements, which showed a decrease in the SSA and pore volume of the silica with the increasing of the extract amount. Morphology of the nanocomposites, investigated by Scanning Electron Microscopy, showed an increased agglomeration in the nanocomposites with the increment of the VV extract amount. Studies on the total phenol quantification and antioxidant activity of the natural extract before and after incorporation in the silica matrix were also carried out. The obtained results indicate that the milling process does not alter the VV extract components, which result to be embedded in the silica matrix. An increase of the antioxidant activity with the increment of the extract amount in the nanocomposites, up to values comparable to the pure VV extract, was also observed.

Phenotyping normal kidney function in elderly patients with type 2 diabetes: a cross-sectional multicentre study.

AIMS: Type 2 diabetes (T2D) accelerates the decline in glomerular function; however, some individuals do not develop chronic kidney disease despite advanced age and long-lasting T2D. We aimed to phenotype patients with T2D aged 80 years or older who presented with a fully preserved kidney function. METHODS: From an Italian population of 281,217 T2D outpatients, we collected data on demographics, anthropometrics, diabetes duration, HbA1c, fasting plasma glucose, lipids, liver enzymes, estimated glomerular filtration rate (eGFR), albumin excretion rate (AER), chronic complications, and medication use. We primarily compared patients with a fully preserved kidney function (eGFR > 90 ml/min/1.73 m2 and AER < 30 mg/24 h, or G1A1) with those with mild kidney impairment (eGFR 60-90 ml/min/1.73 m2 and AER < 30 mg/24 h, or G2A1). RESULTS: N = 113,860 had available data for eGFR and AER, 21,648 of whom were aged ≥ 80. G1A1 (n = 278) and G2A1 (n = 6647) patients represented 1.3 and 30.7% of aged T2D patients, respectively, with an average diabetes duration of 16 years. Differences between the G1A1 and G2A1 groups were entered in a multiple logistic regression analysis with and without imputation of missing data. After adjustment and in both imputed and non-imputed datasets, younger age, lower BMI and lower triglycerides were associated with fully preserved versus mildly impaired kidney function. The comparison between G1A1 and G1A2/3 yielded different results. CONCLUSIONS: In a rare population of patients with a fully preserved kidney function despite old age and long-lasting diabetes, lower BMI and triglycerides suggest that protection from lipotoxicity may preserve kidney function over time.

Elevated serum creatinine and hyponatraemia as prognostic factors in canine acute pancreatitis.

OBJECTIVE: To evaluate prognostic factors for canine acute pancreatitis (AP) based on clinical and laboratory data that can be easily assessed in veterinary practice. DESIGN: Retrospective study between January 2010 and December 2013. METHODS: The diagnosis of AP was based on clinical signs and an abnormal SNAP® cPL™ test result, concurrently with an ultrasound pattern suggestive of pancreatitis. Dogs were divided into survivors and non-survivors. We evaluated 12 clinical and laboratory parameters: respiratory rate, rectal temperature, white blood cells, haematocrit, total serum proteins, albumin, creatinine, cholesterol, total and ionised calcium, sodium and potassium. Clinical and clinicopathological data were statistically compared between survivors and non-survivors. A value of P < 0.05 was considered significant and P < 0.01 as highly significant. The odds ratio (OR) was calculated. RESULTS: The study enrolled 50 client-owned dogs with a diagnosis of AP. Serum creatinine (P = 0.017) and sodium (P = 0.004) correlated significantly with the outcome. Serum sodium < 139.0 mmol/L (139.0 mEq/L) and serum creatinine > 212 µmol/L (2.4 mg/dL) were associated significantly with poor prognosis. Azotaemia (OR 12.5; 95% confidence interval (CI) 1.32-118.48) and hyponatraemia (OR 4.9; 95% CI 1.36-17.64) were associated with increased risk of death. CONCLUSIONS: In dogs with AP, hyponatraemia and azotaemia seem to be significantly associated with an increased risk of death.

Development of curcumin loaded sodium hyaluronate immobilized vesicles (hyalurosomes) and their potential on skin inflammation and wound restoring.

In the present work new highly biocompatible nanovesicles were developed using polyanion sodium hyaluronate to form polymer immobilized vesicles, so called hyalurosomes. Curcumin, at high concentration was loaded into hyalurosomes and physico-chemical properties and in vitro/in vivo performances of the formulations were compared to those of liposomes having the same lipid and drug content. Vesicles were prepared by direct addition of dispersion containing the polysaccharide sodium hyaluronate and the polyphenol curcumin to a commercial mixture of soy phospholipids, thus avoiding the use of organic solvents. An extensive study was carried out on the physico-chemical features and properties of curcumin-loaded hyalurosomes and liposomes. Cryogenic transmission electron microscopy and small-angle X-ray scattering showed that vesicles were spherical, uni- or oligolamellar and small in size (112-220 nm). The in vitro percutaneous curcumin delivery studies on intact skin showed an improved ability of hyalurosomes to favour a fast drug deposition in the whole skin. Hyalurosomes as well as liposomes were biocompatible, protected in vitro human keratinocytes from oxidative stress damages and promoted tissue remodelling through cellular proliferation and migration. Moreover, in vivo tests underlined a good effectiveness of curcumin-loaded hyalurosomes to counteract 12-O-tetradecanoilphorbol (TPA)-produced inflammation and injuries, diminishing oedema formation, myeloperoxydase activity and providing an extensive skin reepithelization. Thanks to the one-step and environmentally-friendly preparation method, component biocompatibility and safety, good in vitro and in vivo performances, the hyalurosomes appear as promising nanocarriers for cosmetic and pharmaceutical applications.

Nanocrystals as tool to improve piroxicam dissolution rate in novel orally disintegrating tablets.

In this paper, orally disintegrating tablets (ODT) were prepared using nanocrystal formulations in order to optimise dissolution properties of lipophilic, poorly soluble drug piroxicam (PRX). Different nanocrystal formulations were prepared using a high pressure homogenisation technique and poloxamer 188 as stabiliser. Characterisation of PRX nanocrystal ODT was carried out by infrared spectroscopy (FTIR), X-ray powder diffractometry (XRPD), differential scanning calorimetry and photon correlation spectroscopy. Dissolution study of PRX ODT was performed in distilled water (pH 5.5) and was compared to that of PRX coarse suspension ODT, PRX/poloxamer 188 physical mixture and bulk PRX samples. The XRPD and FTIR studies demonstrated that the homogenisation process led to a polymorphic transition from form I (bulk commercial PRX) to form III and monohydrate form of the nanocrystals. All ODT formulations prepared using PRX nanosuspensions showed a higher PRX dissolution rate compared with the ODT prepared with the coarse PRX. Since the solubility of the different PRX polymorphic forms increased only slightly from bulk PRX (form I) to monohydrate, form II and form III, we can conclude that the improvement in PRX dissolution rate is mainly caused by the increased surface-to-volume ratio due to the submicron dimension of the drug particles.

De novo everolimus-based therapy in renal transplant recipients: effect on proteinuria and renal prognosis.

BACKGROUND: In large-scale clinical trials, the proliferation signal inhibitor (PSI) everolimus (EVL) combined with cyclosporine (CsA) and steroids, has been shown to be efficacious among de novo renal transplant recipients. Development of proteinuria has been shown to be an important predictor of renal dysfunction after conversion from CsA to a PSI-based regimen, and a key marker of allograft disease progression. Whether EVL de novo treatment is associated with a similar proteinuric effect is still under investigation. METHODS: We compared the development of proteinuria among a cohort of 24 renal transplant recipients who were prescribed EVL (3 mg/d; n = 12; high-dose group) or 1.5 mg/d (n = 12; standard-dose group), in association with CsA, versus third control cohort of 12 patients who received mycophenolate mofetil (control group). EVL doses were adjusted to achieve trough blood levels of 3-8 ng/mL and 8-12 ng/mL among the standard and high-dose groups, respectively. We assessed renal function and protein excretion over a 2-year observation. RESULTS: The high-dose group showed a trend toward greater proteinuria than the standard-dose on control groups. They showed significantly greater proteinuria from 9 months until 2 years; 0.86 +/- 0.5, 0.5 +/- 0.3, 0.47 +/- 0.2 g/24 h (P = .03 and P = .02, respectively, at 24 months). Mean proteinuria significantly correlated with mean EVL doses (n = .73; P = .0001). Concomitantly, the estimated glomerular filtration rate (eGFR) was significantly lower among patients treated with EVL 3.0 versus 1.5 mg/d (53.7 +/- 24 vs 73.04 +/- 17.6 mL/min; P = .037). Among patients in the standard-dose, the eGFR was consistently higher than the control group (62.6 +/- 29 mL/min). CONCLUSION: EVL/CsA therapy is a safe alternative regimen for de novo renal transplant recipients. Higher EVL doses are correlated with greater increases in proteinuria. The standard EVL dose seems to be useful treatment strategy to prevent acute rejection episodes, with a better renal prognosis in the long term.

Chitosomes as drug delivery systems for C-phycocyanin: preparation and characterization.

The aim of this work was to investigate chitosomes, i.e. liposomes coated by a polyelectrolyte complex between chitosan (CH) and xantan gum (XG), as potential delivery system for oral administration of the protein C-phycocyanin. To this purpose several CH-XG-microcomplexes were prepared in aqueous lactic acid at different chitosan-xanthan gum percent ratios and rheological properties of the microcomplexes were studied to analyse the contribution of chitosan and xanthan gum in the reaction of microcomplexation. After establishing the best microcomplexes, chitosomes were prepared by coating C-phycocyanin loaded liposomes with the CH-XG hydrogels using spray-drying or freeze-drying. The chitosomes were characterized in terms of morphology, size distribution, zeta potential, swelling properties, drug release, and mucoadhesive properties. Rheological studies showed the influence of xanthan gum in the microcomplex properties. Moreover, obtained results demonstrated the effects of formulation and process variables on particle size, drug content, swelling, drug release, and especially on the mucoadhesiveness of C-PC chitosomes of CH-XG. In particular, chitosomes prepared by spray-drying technique using CH-XG in 0.5/8.0 (w/w) ratio showed a regular surface and a drug release characteristic for a Fickian diffusion of the active ingredient. The in vitro mucoadhesive study revealed that the spray-drying method is advantageous to prepare C-phycocyanin loaded chitosomes with excellent mucoadhesive properties for colonic drug delivery.

Lack of association between mtDNA haplogroups and Alzheimer's disease in Tuscany.

Mitochondrial DNA (mtDNA) haplogroup-specific polymorphisms were previously related to several neurodegenerative diseases, including Alzheimer's disease (AD). However, the precise role of mtDNA haplogroups in the neurodegenerative cascade leading to AD is still unclear. In this work we have genotyped predefined European mtDNA haplogroups in 209 patients with AD and 191 matched controls. In order to minimise the risk of "genetic contamination", which could lead to false associations between gene markers and disease, we were careful to enrol in the study only patients and controls of clear Tuscan origin (with at least three generations of Tuscanborn relatives). The frequency of the haplogroups did not differ between the two groups, and no correlation with gender, ApoE genotype, age of onset or disease status was observed. Further studies will be required to define the contribution of mtDNA haplogroups, if any, to the pathogenesis of AD. A correct population selection, in order to minimise the risk of genetic contamination, is essential in these studies.

Enteral tube feeding for amyotrophic lateral sclerosis/motor neuron disease.

BACKGROUND: Enteral feeding (tube feeding) is offered to many people with amyotrophic lateral sclerosis/motor neuron disease experiencing difficulty swallowing (dysphagia) and maintaining adequate nutritional intake leading to weight loss. OBJECTIVES: The aim of this review is to examine the efficacy of percutaneous endoscopic gastrostomy placement or other tube feeding placement on: (1) survival; (2) nutritional status; (3) quality of life. Another aim is to examine the minor and major complications of percutaneous endoscopic gastrostomy. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Register (June 2005), MEDLINE (from January 1966 to June 2005), and EMBASE (from January 1980 to June 2005) for randomized controlled trials. In addition we searched MEDLINE (January 1966 to June 2005) and EMBASE (January 1980 to June 2005) to identify non-randomized studies that might be worthy of review and discussion. We checked references in published articles, proceedings of scientific meetings, and enlisted personal communications to identify any additional references. SELECTION CRITERIA: All randomized and quasi-randomized controlled trials were to have been selected. Since no such trials were discovered, all prospective and retrospective controlled studies were reviewed in the 'Background' or 'Discussion' sections of the review. DATA COLLECTION AND ANALYSIS: We independently assessed study methodological design and extracted data. We considered the following outcomes: (1) survival rate in months (of primary interest), (2) nutritional status measured by weight change, change in body mass index, or other quantitative index of nutritional status, and (3) self-perceived quality of life We were also interested in reports of safety of the procedure as indicated by (4) minor and major complications of percutaneous endoscopic gastrostomy or other feeding tube placement. MAIN RESULTS: We found no randomized controlled trials comparing the efficacy of enteral tube feeding with those people who continued to eat orally, without enteral feeding. We summarized the results of retrospective and prospective case controlled studies in the 'Discussion' section of this review. AUTHORS' CONCLUSIONS: There are no randomized controlled trials to indicate whether enteral tube feeding is beneficial compared to continuation of oral feeding for survival. The 'best' evidence to date, based on controlled prospective cohort studies, suggests an advantage for survival in all people with amyotrophic lateral sclerosis/motor neuron disease, but these conclusions are tentative. Evidence for improved nutrition is also incomplete but tentatively favorable. Quality of life has only been addressed by a few researchers and needs more serious attention.

The extent of right-to-left shunt fails to correlate with severity of clinical picture in migraine with aura.

Several investigations have documented an increased incidence of right-to-left shunt (RLS) in migraine with aura (MA) and have emphasised its role in the physiopathology of aura; so far, however, no data are available concerning a possible correlation between the extent of the RLS and the clinical picture of MA patients. To investigate the possible relationship between the extent of the RLS, revealed by the number of microbubbles (MB) detected during transcranial Doppler with IV injection of ultrasound contrast (TCDc), and the clinical characteristics of MA (age at first onset of migraine, mean annual frequency of attacks and mean duration of the aura phase), 30 consecutive patients with typical aura and migraine headache positive on TCDc evaluation for RLS were enrolled. Permanent RLS was found in 12 patients and latent RLS was found in 18 patients; of these, 6 had a high-grade RLS, 5 medium-grade RLS and 7 low-grade RLS. No correlation has been documented between the number of MBs and the clinical parameters of both patients with latent shunts and those with permanent ones, nor between the clinical parameters of the two groups of patients. These data show that RLS does not seem to affect the clinical manifestation of MA and that the extent of RLS fails to correlate with the severity of the clinical picture of the disorder.

Serotoninergic polymorphisms (5-HTTLPR and 5-HT2A): association studies with psychosis in Alzheimer disease.

Patients with Alzheimer disease (AD) often exhibit psychotic symptoms associated with cognitive impairment. A few association studies have been carried out to determine if the serotonin transporter and receptor genes are potential risk factors for AD and/or associated psychopathology. The aim of this study was to investigate the association of a serotonin transporter gene-linked polymorphic region (5-HTTLPR) and the 5-HT2A receptor T102C polymorphism with the risk of developing dementia and/or psychotic symptoms in a group of sporadic AD patients from Italy. No significant differences in the distribution of allele and genotype frequencies of 5-HTTLPR and 5-HT2A T102C were found between patient and control groups. However, a significant association between the C102/C102 5-HT2A genotype and psychotic symptoms (p < 0.001) was observed. Our data strongly confirm results from previous studies suggesting that the C102 allele of the 5-HT2A receptor is associated with the occurrence of psychotic symptoms in AD. On the contrary, the serotonin transporter does not appear to be a major susceptibility factor in the pathophysiology of the disease.

Bayesian approach to searching for susceptibility genes: Gc2 and EsD1 alleles and multiple sclerosis.

Multiple sclerosis (MS) is one of the most common causes of neurological disability in early adulthood. The current literature is interested in identifying biological or DNA markers associated with genetic susceptibility to MS. The aim of this study is to investigate, by means of Bayesian statistical inference, whether the presence of Gc2 (Gc = group-specific component) and/or EsD1 (EsD = esterase D) alleles affects MS susceptibility. Gc and EsD are two classical genetic markers, being the first a serum protein polymorphism, the latter an isoenzyme polymorphism. The interest of the proposed statistical approach of searching for MS susceptibility genes relies on the analysis of two different functions, one function being inferred from our results on 56 unrelated patients from central Italy affected by MS, the other one from Italian and worldwide epidemiological data. The graphical analysis suggests that MS susceptibility is influenced by both Gc2 and EsD1 alleles; and EsD1 allele is more informative than Gc2. These results point out the advantages of the Bayesian approach in searching for susceptibility genes. Furthermore, the significant association between the considered alleles and the susceptibility to MS suggests possible hypotheses about the pathogenesis of the disease.

Coenzyme Q10, exercise lactate and CTG trinucleotide expansion in myotonic dystrophy.

Steinert's myotonic dystrophy (DM) is a genetic autosomal dominant disease and the most frequent muscular dystrophy in adulthood. Although causative mutation is recognized as a CTG trinucleotide expansion on 19q13.3, pathogenic mechanisms of multisystem involvement of DM are still under debate. It has been suggested that mitochondrial abnormalities can occur in this disease and deficiency of coenzyme Q 10 (CoQ10) has been considered one possible cause for this. The aim of this investigation was to evaluate, in 35 DM patients, CoQ10 blood levels and relate them to the degree of CTG expansion as well as to the amount of lactate production in exercising muscle as indicator of mitochondrial dysfunction. CoQ10 concentrations appeared significantly reduced with respect to normal controls: 0.85 +/- 0.25 vs. 1.58 +/- 0.28 microg/ml (p < 0.05). Mean values of blood lactate were significantly higher in DM patients than controls (p < 0.05) both in resting conditions (2.9 +/- 0.55 vs. 1.44 +/- 1.11 mmol/L) and at the exercise peak (6.77 +/- 1.79 vs. 4.90 +/- 0.59 mmol/L), while exercise lactate threshold was anticipated (30-50% vs. 60-70% of the predicted normal maximal power output, p < 0.05). Statistical analysis showed that serum CoQ10 levels were significantly (p < 0.05) inversely correlated with both CTG expansion degree and lactate values at exercise lactate threshold level. Our data indicates the occurrence of reduced CoQ10 levels in DM, possibly related to disease pathogenic mechanisms associated with abnormal CTG trinucleotide amplification.

Impaired oxidative metabolism in exercising muscle from ALS patients.

The pathogenic mechanism of selective loss of motor neurones in amyotrophic lateral sclerosis (ALS) is still poorly understood. Recently, research evidence has suggested that mitochondrial dysfunction occurs in central nervous system as well as in peripheral tissues from ALS patients. The aim of our study was to indirectly investigate in vivo oxidative metabolism of exercising muscle in a case history of patients affected by ALS. To this purpose 11 patients, 8 male and 3 female, mean age+/-SD: 52.4+/-11.1 years, performed a bicycle incremental test for the assessment of lactate production. At rest, there was increased lactate concentration in patients: 2.77+/-0.79 vs. 1.48+/-0.49 mmol/l in normal controls (normal range: 0.67-2.47 mmol/l). Analysis of lactate curve during exercise showed a lactate production increase compared to controls. Furthermore, anaerobic lactate threshold was detected at 40-50% of the predicted normal power output, anticipated with respect to both normal subjects and non-ALS chronically denervated controls with comparable motor impairment (60-70%), suggesting that mitochondrial dysfunction can occur in exercising skeletal muscle from ALS patients.

Mexiletine in the treatment of torticollis and generalized dystonia.

Mexiletine is an antiarrhythmic drug that has been reported to exert antidystonic properties. We performed an open-label study to collect further evidence of the antidystonic effect of mexiletine in spasmodic torticollis (ST) and to evaluate its possible use in generalized dystonia. We administered mexiletine to six patients with dystonia (three with generalized dystonia and three with ST) who had failed to respond to previous pharmacotherapy. The drug was started at a dose of 200 mg/d by mouth and increased up to a maximum dose of 800 mg/d. Patients were evaluated at regular intervals over a 6-week period with use of the Fahn & Marsden Dystonia Scale and the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and videotaped. At the end of the trial, the videotapes were reviewed and scored by a blind observer. Patients were then followed for at least 1 year and evaluated every 3 months at the dose reached during the study period. No adverse effects were reported in five patients; in one patient, dizziness developed at the dosage of 800 mg/d, requiring a reduction of the dose. At the end of a 6-week period, a significant improvement in the rating scale for dystonia and in videotape ratings was observed after mexiletine treatment (p < 0.01). Our data indicate that mexiletine is a useful drug in dystonia treatment.

Effects of aerobic training on lactate and catecholaminergic exercise responses in mitochondrial myopathies.

The aim of this study was to evaluate the effects of an aerobic training program on the metabolic and sympathetic responses to exercise in 12 patients with mitochondrial myopathies. A 10-week course of aerobic training, consisting of supervised exercise every other day on an electrically braked pedal-rate bicycle ergometer was prescribed to each patient and four healthy controls. Venous lactate, epinephrine (EP) and norepinephrine (NEP) levels were assessed at baseline and after the aerobic training by means of constant-workload exercise performed at near lactate threshold (LT). In patients, a decrease in exercise peak values, significant for lactate (-38.6%, P < 0.01) but not for catecholamines (EP: -26.0%, NEP: -22.1%) was observed after training, findings confirmed by the lactate/EP and lactate/NEP area ratios. The results show that lactate accumulation during exercise is decreased after aerobic training in mitochondrial myopathies and that the effect is partially dissociated from the catecholaminergic response. This in turn suggests that the lactate decrease can be explained, at least in part, by the improved muscle oxidative metabolism consequent to the proposed training program.

Abnormal H-Tfam in a patient harboring a single mtDNA deletion.

We report on a patient suffering from a progressive mitochondrial disorder characterized by ocular myopathy, exercise intolerance, and muscle wasting. Morphological examination of muscle biopsy showed increased variability in fiber size and scattered ragged-red fibers. Analysis of muscle mitochondrial DNA by Southern blot and PCR revealed a heteroplasmic single deletion of 4100 base pairs, located between nucleotide positions 8300 and 12,400. Western blot analysis showed high levels of the human mitochondrial transcription factor A (Tfam). Interestingly, we also detected an additional Tfam product, of approximately 22 kDa. This is the first case in which a qualitatively abnormal Tfam has been found to be associated with a mitochondrial disorder in humans.

Abnormal levels of human mitochondrial transcription factor A in skeletal muscle in mitochondrial encephalomyopathies.

Human mitochondrial transcription factor A (hmtTFA or Tfam), a 25-kDa protein encoded by a nuclear gene located on chromosome 10q21, is involved in the control of replication and transcription of mtDNA. To better understand the complex relationship between h-mtTFA and mitochondrial function, we assessed by western blot the levels of h-mtTFA in skeletal muscle from 7 patients affected by mitochondrial diseases (MD) caused by different mtDNA mutations. We related these results to exercise lactate production as well as to the pathologic features of the underlying myopathy. h-mtTFA levels were significantly inversely related to blood lactate and the percent of RRF, borderline to cox negative fibers. Our results indicate that hmtTFA may be involved in the cascade of events which determine functional impairment of MD.

Cortical silent period in patients with amyotrophic lateral sclerosis.

Transcranial magnetic stimulation (TMS) during a muscle contraction induces a motor-evoked potential (MEP) in the skeletal muscle followed by a cessation of EMG activity, the cortical silent period (C-SP). The C-SP is a useful parameter to indicate the activation of the motor system. Accurate determination of the C-SP can be important in amyotrophic lateral sclerosis (ALS), a progressive disorder of unknown etiology characterised by degeneration of upper and lower motor neurons. The aim of this study was to evaluate the sensitivity of C-SP as an index of motor system involvement, in ten patients affected by ALS, with a mean duration of the disease: 5. 5+/-3.4 months, by means of an objective computer-aided method to measure C-SP and its relationship to stimulation intensity. C-SP duration was significantly reduced in ALS patients compared to controls at low stimulation intensity corresponding to an MEP threshold increased by 15%. While in less severely affected patients C-SP duration approached control values at higher stimulation intensities (25 and 50% upper MEP threshold), in more severe ALS subjects it showed a further reduction, allowing them to be discriminated.