Sildenafil improves endothelial function in patients with pulmonary hypertension

BACKGROUND: Sildenafil has been shown to be effective in the treatment of pulmonary hypertension, and has favourable effects on endothelial function. Our hypothesis is that a part of the beneficial effects of sildenafil in patients with pulmonary hypertension is due to the improvement of the endothelial function. METHODS: Nine patients (seven females, age 67+/-9 years) with thromboembolic pulmonary hypertension were treated with sildenafil, at a mean dose of 150+/-75 mg/die. At baseline and after 6 months all patients underwent: right-heart catheterization, 6-min walking distance, and a study of endothelial function, including the measure of the flow-mediated vasodilation of the brachial artery, and the dosage of plasma levels of endothelin-1 and von Willebrand factor. RESULTS: During follow-up we found a significant reduction of mean pulmonary artery pressure and arteriolar resistances. Accordingly, the functional capacity improved (an average of+37 m). Sildenafil improved endothelial-dependent vasodilation and reduced plasma concentrations of endothelin-1 (from 4.5+/-0.6 to 3.1+/-0.7 pg/mL; p<0.0001) and von Willebrand factor (from 183.1+/-10.1 to 149.1+/-17.6 mU/mL; p<0.0001). CONCLUSION: Improvement of the endothelial function may represents one of the mechanisms able to explain the favourable effects sildenafil has shown in patients with pulmonary hypertension.     

Effects of carbohydrate counting on glucose control and quality of life over 24 weeks in adult patients with type 1 diabetes on continuous subcutaneous insulin infusion: a randomized, prospective clinical trial (GIOCAR)

OBJECTIVE

Few studies have assessed the efficacy of carbohydrate counting in type 1 diabetes, and none have validated its efficacy in patients who are treated with continuous subcutaneous insulin infusion (CSII). The aim of our study was to test the effect of carbohydrate counting on glycemic control and quality of life in adult patients with type 1 diabetes who are receiving CSII.

RESEARCH DESIGN AND METHODS

Sixty-one adult patients with type 1 diabetes treated with CSII were randomly assigned to either learning carbohydrate counting (intervention) or estimating pre-meal insulin dose in the usual empirical way (control). At baseline and 12 and 24 weeks, we measured HbA_1c, fasting plasma glucose, BMI, waist circumference, recorded daily insulin dose, and capillary glucose data, and administered the Diabetes-Specific Quality-of-Life Scale (DSQOLS) questionnaire.

RESULTS

Intention-to-treat analysis showed improvement of the DSQOLS score related to diet restrictions (week 24 – baseline difference, P = 0.008) and reduction of BMI (P = 0.003) and waist circumference (P = 0.002) in the intervention group compared with control subjects. No changes in HbA_1c, fasting plasma glucose, daily insulin dose, and hypoglycemic episodes (<2.8 mmol/L) were observed. Per-protocol analysis, including only patients who continuously used carbohydrate counting and CSII during the study, confirmed improvement of the DSQOLS score and reduction of BMI and waist circumference, and showed a significant reduction of HbA_1c (−0.35% vs. control subjects, P = 0.05).

CONCLUSIONS

Among adult patients with type 1 diabetes treated with CSII, carbohydrate counting is safe and improves quality of life, reduces BMI and waist circumference, and, in per-protocol analysis, reduces HbA_1c.Nutritional management is a cornerstone in the management of diabetes, and monitoring of carbohydrate intake, a major determinant of postprandial blood glucose, is a key strategy for achieving good glucose control (1–4).Some studies have examined the contribution of quantity and type (i.e., simple vs. complex) of carbohydrates in patients with type 1 diabetes and showed that the daily insulin requirement is indeed associated with the amount rather than the type of daily carbohydrate intake (4–6).Over the years, a number of methods have been proposed to help patients with diabetes to quantify the carbohydrate content of a meal in real life, for example, exchange lists, portion/servings, grams, glycemic index, and insulin:carbohydrate ratio (I:CHO) (7–9). Among these, the I:CHO is considered the most advanced counting technique, consisting of estimating the grams of carbohydrates in a meal and then calculating the pre-meal insulin dose based on this estimation and an insulin sensitivity measure (8). Carbohydrate counting was devised in the 1960s, but it has become widely used as part of intensive diabetes management after the Diabetes Control and Complications Trial (DCCT) (10,11).Although carbohydrate counting is widely used by patients worldwide, few studies have validated its efficacy in type 1 diabetes (12,13), and none have validated its efficacy in adult patients receiving continuous subcutaneous insulin infusion (CSII). We designed the current study with the aim of testing the effect of carbohydrate counting on glucose control and quality of life over 24 weeks in adult patients with type 1 diabetes treated with CSII.     

Differential diagnosis by unenhanced FLAIR T2-weighted magnetic resonance images between solitary high grade gliomas and cerebral metastases appearing as contrast-enhancing cortico-subcortical lesions

The aim was to assess the value of unenhanced fluid-attenuated inversion recovery T2-weighted sequences (FLAIR-T2) in the differential diagnosis between solitary high-grade gliomas (HGG) and cerebral metastases (CM) appearing as contrast-enhancing cortico-subcortical lesions of the brain. In 69 patients with a contrast-enhancing cortico-subcortical brain lesion (43 HGG, and 26 CM), unenhanced FLAIR-T2 and gadolinium-enhanced FLAIR T1-weighted (Gd-FLAIR-T1) axial images have been reviewed for the involvement of the cortex adjacent to the contrast-enhancing lesion. In 27 (62.79%) out of 43 HGG, and 3 (11.53%) out of 26 CM, the cortex adjacent to the contrast-enhancing lesion showed high signal intensity on unenhanced FLAIR-T2 without enhancement at Gd-FLAIR-T1. Fischer’s exact probability test was P = 0.0003 when applied to HGG versus CM categories, indicating a significant difference. The high signal intensity on unenhanced FLAIR-T2 without gadolinium-enhancement of the cortex adjacent to the enhancing lesion is more frequently associated with HGG than CM.     

Phenotype modulators in myophosphorylase deficiency

Myophosphorylase deficiency is characterized by exercise intolerance, muscle cramps, and recurrent myoglobinuria. Some patients are severely affected, whereas others are minimally affected or asymptomatic. The molecular basis of the disease has been elucidated but does not provide an explanation for the clinical variability. In a large cohort of patients with myophosphorylase deficiency, we tested the hypothesis that polymorphic variants in either myoadenylate deaminase (MADA) or angiotensin-converting enzyme (ACE) could act as modulators of phenotype expression. Forty-seven patients were evaluated. Clinical severity was assessed according to a severity scale of four grades. MADA activity was studied by histochemical and biochemical analysis of muscle, and the Q12X mutation in the adenine monophosphate deaminase 1 gene (AMPD1) and the insertion/deletion polymorphism in the ACE gene were assessed genetically. A complete MADA defect together with the Q12X mutation was detected in one severely affected patient. Eleven patients were heterozygous for the Q12X mutation. There was no association between clinical grading and MADA status. In contrast, we found a highly significant (p < 0.01) association between ACE genotype and clinical severity, with strong correlation between severe phenotype and number of D alleles. We show that ACE insertion/deletion polymorphism may play a significant role as phenotype modulator in McArdle's disease.     

Syringomyelia associated with Chiari I malformation

An 18-year-old man with progressive paraparesis, thermal hypoesthesia, sweating abnormalities, bladder dysfunction, severe orthostatic hypotension, bilateral Babinski sign, underwent a brain MRI scan that showed downward displacement of cerebellar tonsils through the foramen magnum, consistent with Chiari I malformation, compression of the brainstem–spinal cord junction, and C1–D11 syringomyelia (6.5 mm diameter at C2 level) consistent with Chiari I syndrome. Suboccipital craniectomy and duraplasty were performed. A C2 partial laminectomy and ablation of posterior arch of the atlas was performed. MRI scans 4 days and 1 month after surgery showed a dramatic syringomyelia reabsorption (2.5 and 1 mm, respectively) associated with complete clinical recovery.     

Lamin A and ZMPSTE24 (FACE-1) defects cause nuclear disorganization and identify restrictive dermopathy as a lethal neonatal laminopathy

Restrictive dermopathy (RD), also called tight skin contracture syndrome (OMIM 275210), is a rare disorder mainly characterized by intrauterine growth retardation, tight and rigid skin with erosions, prominent superficial vasculature and epidermal hyperkeratosis, facial features (small mouth, small pinched nose and micrognathia), sparse/absent eyelashes and eyebrows, mineralization defects of the skull, thin dysplastic clavicles, pulmonary hypoplasia, multiple joint contractures and an early neonatal lethal course. Liveborn children usually die within the first week of life. The overall prevalence of consanguineous cases suggested an autosomal recessive inheritance. We explored nine fetuses/newborns children with RD. Two were found to have an heterozygous splicing mutation in the LMNA gene, leading to the complete or partial loss of exon 11 in mRNAs encoding Lamin A and resulting in a truncated Prelamin A protein. Lamins are major constituents of the nuclear lamina, a filamentous meshwork underlying the inner nuclear envelope. In the other seven patients, a unique heterozygous insertion leading to the creation of a premature termination codon was identified in the gene ZMPSTE24, also known as FACE-1 in human. This gene encodes a metalloproteinase specifically involved in the post-translational processing of Lamin A precursor. In all patients carrying a ZMPSTE24 mutation, loss of expression of Lamin A as well as abnormal patterns of nuclear sizes and shapes and mislocalization of Lamin-associated proteins was evidenced. Our results indicate that a common pathogenetic pathway, involving defects of the nuclear lamina and matrix, is involved in all RD cases. RD is thus one of the most deleterious laminopathies identified so far in humans caused by (primary or secondary) A-type Lamin defects and nuclear structural and functional alterations.     

Expression and phosphorylation of delta-CaM kinase II in cultured Alzheimer fibroblasts

Dysregulation of calcium homeostasis is among the major cellular alterations in Alzheimer's disease (AD). We studied Ca(2+)/calmodulin-dependent protein kinase II (CaM kinase II), one of the major effectors regulating neuronal responses to changes in calcium fluxes, in cultured skin fibroblasts from subjects with sporadic AD. We found, by using PCR and Western analysis, that human fibroblasts express the delta-isoform of this kinase, and that CaM kinase II is the major Ca(2+)/calmodulin-dependent kinase in these cells. Protein expression level of the kinase was not significantly different in AD fibroblasts. However, the total activity of the kinase (stimulated by Ca(2+)/calmodulin) was significantly reduced in AD cell lines, whereas Ca(2+)-independent activity was significantly enhanced. The percent autonomy of the kinase (%Ca(2+)-independent/Ca(2+)-dependent activity) in AD cell lines was 62.8%, three-fold the corresponding percentage in control fibroblasts. The abnormal calcium-independent activity was not due to enhanced basal autophosphorylation of Thr(287). The observed abnormalities, if present in brain tissue, may be implicated either in dysfunction of neuroplasticity and cognitive functions or in dysregulation of cell cycle.     

Loss of ZMPSTE24 (FACE-1) causes autosomal recessive restrictive dermopathy and accumulation of Lamin A precursors

Restrictive dermopathy (RD) is characterized by intrauterinegrowth retardation, tight and rigid skin with prominent superficialvessels, bone mineralization defects, dysplastic clavicles,arthrogryposis and early neonatal death. In two patients affectedwith RD, we recently reported two different heterozygous splicingmutations in the LMNA gene, leading to the production and accumulationof truncated Prelamin A. In other patients, a single nucleotideinsertion was identified in ZMPSTE24. This variation is locatedin a homopolymeric repeat of thymines and introduces a prematuretermination codon. ZMPSTE24 encodes an endoprotease essentialfor the post-translational cleavage of the Lamin A precursorand the production of mature Lamin A. However, the autosomalrecessive inheritance of RD suggested that a further moleculardefect was present either in the second ZMPSTE24 allele or inanother gene involved in Lamin A processing. Here, we reportnew findings in RD linked to ZMPSTE24 mutations. Ten RD patientswere analyzed including seven from a previous series and threenovel patients. All were found to be either homozygous or compoundheterozygous for ZMPSTE24 mutations. We report three novel ‘null’mutations as well as the recurrent thymine insertion. In allcases, we find a complete absence of both ZMPSTE24 and matureLamin A associated with Prelamin A accumulation. Thus, RD iseither a primary or a secondary laminopathy, caused by dominantde novo LMNA mutations or, more frequently, recessive null ZMPSTE24mutations, most of which lie in a mutation hotspot within exon9. The accumulation of truncated or normal length Prelamin Ais, therefore, a shared pathophysiological feature in recessiveand dominant RD. These findings have an important impact onour knowledge of the pathophysiology in Progeria and relateddisorders and will help direct the development of therapeuticapproaches.