Electrophysiological features in acromegaly: re-thinking the arrhythmic risk?

BACKGROUND

Acromegaly is disease associated with a specific cardiomyopathy. Hitherto, it has been widely understood that acromegaly carries an increased risk of arrhythmia.

PURPOSE

In this review we show that evidences are limited to a small number of case-control studies that reported increased rates of premature ventricular beats (PVB) but no more significant arrhythmia. In contrast, there are several studies that have reported impaired preclinical markers of arrhythmia, including reduced heart rate variability, increased late potentials, QT interval dispersion, impaired heart rate recovery after physical exercise and left ventricular dysynchrony. Whilst these markers are associated with an adverse cardiovascular prognosis in the general population, they do not have a high independent positive predictive accuracy for arrhythmia. In acromegaly, case reports have described sudden cardiac death, ventricular tachyarrhythmia and advanced atrio-ventricular block that required implantation of a cardio-defibrillator or permanent pacemaker. Treatment with somatostatin analogues can reduce cardiac dysrhythmia in some cases by reducing heart rate, PVBs and QT interval. Pegvisomant reduces mean heart rate. Pasireotide is associated with QT prolongation. In the absence of good quality data on risk of arrhythmia in acromegaly, the majority of position statements and guidelines suggest routine 12-lead electrocardiography (ECG) and transthoracic echocardiography (TTE) in every patient at diagnosis and then follow up dependent on initial findings.

A contribution to adequate use of freshwater sponges as a proxy in paleoenvironmental studies

This paper provides a comprehensive review of the environments where freshwater sponges occur and evaluates the use of sponge spicules as a proxy in paleoenvironmental studies in the Neotropical region. The paper aims to: I) review the information about the ecology of inland sponges to facilitate the use of spicules as a paleoenvironmental tool; and II) identify possible incongruities in the use of this information in paleoenvironmental reconstructions that have been conducted in Neotropical regions. The study compiled data on 77 sponge species, specialist or generalist that occur under certain environmental conditions, such as: substrate type for growth, hydrodynamic types, as well as salinity and acidity concentrations. In addition, it provides a comparison of the paleoenvironmental conditions applied to reconstruction studies that have been carried out within this biogeographic region, highlighting incongruities regarding the current ecology of the sponges.

Ovarian 25OH-vitamin D production in young women affected by polycystic ovary syndrome

INTRODUCTION

Vitamin D is involved in the regulatory mechanisms of ovarian function and is frequently low in PCOS patients. Since obesity and hyperinsulinemic state negatively influenced vitamin D levels, therefore, we evaluated the production of vitamin D at the ovarian level only in lean and normoinsulinemic PCOS subjects. Basal, GnRH analogue-induced ovarian production of 25OH-vitamin D (VitD) and a direct sampling at ovarian vein level were investigated.

METHODS

Basal and GnRH analogue-induced hormone levels were evaluated at peripheral level in 45 subjects, aged 18-39 years, and in 22 healthy women with age- and BMI-matched as controls. In 12 PCOS patients, undergoing laparoscopy, a venous sampling at both peripheral and ovarian level was further done. All subjects presented low VitD levels, appropriate to the season and with no difference between PCOS and control subjects.

RESULTS

GnRH analogue significantly stimulated plasma LH, FSH, 17-OHP and estradiol secretion (p from < 0.05 to < 0.001 vs basal levels), whereas no effect was observed on both serum AMH and VitD concentrations in all groups. A significant difference (p < 0.006), between peripheral and ovarian veins, was observed in both AMH and estradiol levels in PCOS subjects, while no gradient of VitD was detected.

CONCLUSIONS

All patients presented with low VitD levels. The absence of any VitD variation, both at basal and after GnRH analogue administration, or at peripheral-ovarian vein gradient, suggests no pituitary-ovarian axis involvement in VitD production or its direct ovarian production in lean and normoinsulinemic PCOS subjects.

Acromegaly and ultrasound: how, when and why?

BACKGROUND

Acromegaly is a rare disease caused by an excess of growth hormone and insulin-like growth factor 1. It is usually diagnosed because of typical signs such as macroglossia, acral enlargement, jaw prognathism and malocclusion. Systemic complications are a major cause of morbidity and mortality in acromegaly, and many patients remain undiagnosed for several years. Increased ultrasound (US) application in the general population, and including among acromegaly patients, has revealed many suggestive features which, taken together with clinical suspicion, could induce suspicion of this disease.

PURPOSE

This review describes main US features in acromegaly. Echocardiography shows a typical cardiomyopathy, characterized by left ventricular hypertrophy, diastolic and systolic dysfunction, aortic and mitral regurgitation, and increased aortic root diameters. US preclinical markers of atherosclerosis, such as intima media thickness (IMT), seem also to be impaired. Visceromegaly and increased organ stiffness are other features of acromegaly, including enlarged prostate, kidneys, liver, and thyroid. In addition, other US findings are: renal cysts, micronephrolithiasis, impairment of renal haemodynamic parameters, gallstones and gallbladder polyps, hepatic steatosis, thyroid nodules, multinodular goiter, and polycystic ovaries. Musculoskeletal US findings are increased cartilage thickness, impaired density and elasticity of bones, nerve enlargement, carpal and cubital tunnel syndrome, and trigger finger.

CONCLUSIONS

Acromegaly patients frequently present systemic complications and a diagnostic delay. US features of acromegaly are not specific, but could potentially have a key role in early detection of the disease in the presence of typical clinical features.

Sleep disorders and cognitive dysfunction in acromegaly

PURPOSE

In the general population, sleep disorders are associated with an increased risk of cognitive impairment. The prevalence of sleep disorders, such as sleep apnea, in acromegalic patients is higher than in the general population, and they may have additional risk of cognitive impairment due to acromegaly treatment and comorbidities. We aim to study the relationship between sleep disturbances and cognitive dysfunction in a group of acromegalic patients.

METHODS

We studied 67 consecutive acromegalic patients. We performed a neurocognitive assessment and patients completed the Acromegaly Quality of Life Questionnaire (AcroQoL), Epworth Sleepiness Scale, and Pittsburgh Sleep Quality Index.

RESULTS

Of the 67 acromegaly patients in the study, 38.8% were male and median age at the neurological examination was 56 (IQR 48, 65). Approximately 6-10% of patients had impaired cognitive assessment, depending on the test. In linear regression models adjusted for age, sex, BMI, disease duration, and disease activity, poorer sleep quality was associated with lower global cognitive z-score (B = -0.03, 95% CI -0.06, -0.002). Daytime somnolence was associated with poorer physical AcroQoL sub-score (B = -0.04, 95% CI -0.08, -0.002). Sleep quality was associated with poorer overall AcroQoL (B = -0.03, 95% CI -0.05, -0.006), physical AcroQoL (B = -0.04, 95% CI -0.07, -0.005), psychological AcroQoL (B = -0.02, 95% CI -0.04, -0.001), and social AcroQoL (B = -0.02, 95% CI -0.04, -0.0009).

CONCLUSIONS

In acromegaly patients, we found robust evidence that poor sleep quality is associated with poorer quality of life, and some evidence that it is associated with poorer cognitive function.

Guidelines versus real life practice: the case of colonoscopy in acromegaly

PURPOSE

The aim of this study is to investigate guideline application and colonoscopy findings in real-life practice in acromegaly.

METHODS

We conducted a retrospective observational non-interventional and cross-sectional analysis on 146 patients with acromegaly (ACRO) referred to our clinic. We evaluated colonoscopy data, focusing on the correlation between colonoscopy findings and hormonal/metabolic values.

RESULTS

The total number of colonoscopies performed in ACRO patients increased from 6 in the period 1990-1994 to 57 in the period 2010-2014. Colonoscopy procedures were performed according to guidelines in 25% of ACRO patients at diagnosis, 51% at follow-up and 11% globally (both at diagnosis and follow-up). Among the 146 ACRO patients, 68% were subjected to at least one colonoscopy and in 32% of the cases a polyp was detected during the procedure. The presence of polyps was significantly associated with mean levels of growth hormone (GH), insulin-like growth factor 1 (IGF-1), fasting glucose and insulin levels (p < 0.05). Polyps were detected in 48% of untreated patients and in 26% of patients under treatment for acromegaly (p = 0.04). The general risk of polyps and adenomatous polyps in ACRO patients was higher compared to the control population of Veneto Region, Italy (odds ratio 1.33 and 1.16, respectively). No cancerous polyps were detected in our analysis.

CONCLUSION

In real-life practice, adherence to ACRO colonoscopy clinical guidelines was lower than expected. Among patients who underwent colonoscopy, the prevalence of colon polyps was higher for ACRO patients, suggesting the need for new strategies to ensure adherence to colonoscopy guidelines.

Development of a whole disc organ culture system to study human intervertebral disc

Study type: Basic science

Objective: Low back pain is one of the most common health problems1 and is strongly associated with intervertebral disc degeneration, (IVD). Current treatments remove the symptoms without reversing or even retarding the underlying problem. Development of new therapy for the regeneration of the degenerative IVD is complicated by the lack of a validated long-term organ culture model in which therapeutic candidates can be studied. The object of this study was to develop, optimize, and validate an organ culture model for human IVD, allowing for the study of degeneration and the potential for regeneration of the human IVD.

Methods: From eleven donors, an average of 5–6 IVDs were obtained. Inclusion criteria were; age between 50 and 70 years old, no history of cancer, chemotherapy, diabetes, or liver cirrhosis. An x-ray of the harvested spine was done to assess the grade of degeneration. Three different methods for isolating the discs were studied: with bony endplate (BEP), without endplate (NEP), and with cartilage endplate (CEP). Discs were cultured for 4 weeks without external load, in Dulbecco's modified eagle media with glucose and fetal bovine serum (FBS). Four different combinations of concentrations of glucose and FBS were compared: low glucose-low FBS, low glucose-high FBS, high glucose-low FBS, and high glucose-high FBS.2 Short-term cultures (1 week) were performed to compare the cell viability of the three methods of isolating the discs. Swelling potential on NEP and CEP discs from the same donor were evaluated. After four weeks of culture, a 4 mm punch was taken from CEP discs and cell viability was evaluated using a live/dead assay with confocal microscopy.

Results: Analyzing the potential of swelling in CEP discs, there was an increase in volume to a maximum of 25% and retention of shape and morphology. Whereas in NEP discs, there was an excessive deformation and a two-fold time increase in volume than CEP discs. The cell viability in short-term cultures is around 40%–50% in the BEP model, 50%–60% in the NEP model and > 96% in the CEP model. BEP isolated discs show endplate necrosis that begins after 4 days of culture. Cell viability in CEP discs was evaluated at 4 weeks in three different areas of the disc: nucleus pulposus, inner annulus fibrosus, and outer annulus fibrosus. We found no difference in live cells (> 96%) between the four different concentrations of FBS and glucose (Table 1).

Conclusions: We have developed a novel method to isolate human IVDs and optimized the culture conditions. The CEP method has been proven to be superior to the previous models (NEP and BEP) in cell viability and maintaining physiologic swelling.3 In the long-term cultures, the CEP system maintained sufficient nutrient supply and high cell survival in all regions of the discs even with low concentrations of FBS and glucose. The availability of an intact disc organ culture system has a considerable advantage over the culture of isolated disc cells, as it maintains the cells in their unique microenvironment, making any response to catabolic or anabolic agents more physiologically relevant.

Venous outflow as a criterion of impairment of cerebral vascular reserve

AIM

The purpose of this work is to evaluate if the asymmetry of venous outflow between the two hemispheres is a reliable criterion of impairment of the cerebral vascular reserve among symptomatic patients harbouring a spontaneous atherosclerotic occlusion of internal carotid artery.

METHODS

From January 1995 to December 2007, 7 symptomatic patients, affected from occlusion of internal carotid artery, were submitted to a low-flow by-pass between the superficial temporal artery and the middle cerebral artery owing to the presence of an impairment of cerebral vascular reserve diagnosed by TC-Doppler, SPECT or perfusion-CT with acetazolamide challenge. Conventional angiography was always performed. Angiographic studies of these patients were reviewed in order to find out the presence of asymmetry of the venous outflow. In the same period 35 patients harbouring an occlusion of the carotid artery in the neck and a normal cerebral reserve underwent cerebral angiography in our departments in Monza. Angiographic studies, of this latter group of patients, were also retrospectively analyzed with the same purpose.

RESULTS

All patients, with a poor cerebral reserve, showed an asymmetry of venous outflow >3 s omolateral at the carotid occlusion. Patients, with a normal cerebral reserve, showed an asymmetry of venous outflow <2 s.

CONCLUSIONS

Asymmetry of venous outflow were correlated to an impaired cerebral reserve also in chronic conditions as atherosclerotic spontaneous occlusion of internal carotid artery. Our data are a further support to the reliability of this criterion in case of therapeutic sacrifice of internal carotid artery.

Hemodynamic instability after extracranial carotid stenting

OBJECTIVE

Hemodynamic instability (hypertension, hypotension and bradycardia) is a well-known complication of carotid endarterectomy. Carotid angioplasty and stenting (CAS) is becoming a valuable alternative treatment for patients with severe carotid stenosis and increased surgical risk. CAS implies instrumentation of the carotid bulb, so baroceptor dysfunction may provoke hemodynamic instability. The aim of this work was to calculate the incidence of this complication and to detect factors to predict it.

METHODS

Medical records and angiograms of 51 consecutive patients submitted to CAS for severe atherosclerotic stenosis (40 cases) or postsurgical restenosis (11 cases) were retrospectively reviewed in order to detect the occurrence of intra- and post-procedural hypertension (systolic blood pressure >160 mmHg), hypotension (systolic blood pressure <90 mmHg) and bradycardia (heart rate <60 beats/min). The relationship between clinical, procedural and angiographic factors and the occurrence of hemodynamic instability was assessed with univariate and multivariate analysis (logistic regression).

RESULTS

Transient mild systolic post-procedural hypertension occurred in five cases (10%); preprocedural hypertension, asymptomatic stenosis and ipsilateral post-surgical restenosis predicted this. Hypotension with bradycardia also occurred in five cases (10%), one with neurological sequelae. Transient periprocedural bradycardia occurred in 19 cases (37%). Severe bradycardia without hypotension arose in one case only. Factors predicting post-procedural hypotension included the presence of a fibrous plaque and the ratio between the pre- and post-stenting diameter of the internal carotid artery. Peri-procedural bradycardia predicted post-procedural bradycardia. None of these factors were confirmed by multivariate analysis as a significant prognostic predictor.

CONCLUSION

Mild systolic hypertension may occur after CAS, but is resolved by medical treatment. Prolonged hypotension and bradycardia may also arise and this can be dangerous because it may cause neurological deterioration due to hypoperfusion. These complications cannot be predicted by clinical, procedural, and angiographic factors.

Deep brain stimulation for the treatment of Parkinson's disease: the experience of the Neurosurgical Department in Monza

deep brain stimulation is a widely accepted surgical therapy for the symptomatic treatment of advanced parkinson's disease; high frequency chronic stimulation of the subthalamic nucleus proved its efficacy to control the major motor symptoms. In the neurosurgical department of Monza we treated 72 parkinsonian patients (November 1998-January 2003). One year follow-up results are: decrease of tremor 90%, hypertonous 56%, bradykinesia 70%, voice impairment amelioration 30%, mean total daily L-dopa intake reduced 58%. Freezing and balance did not ameliorate, some voice impairment and psychic derangement have been observed. Major surgical complications were: haemorrage (1 case - transient hemiparesis), infections (2 cases), pulmonary embolisation (1 case). To optimise the surgical results, careful clinical and instrumental selection of the patients are mandatory before surgery.

MRI indirect stereotactic targeting for deep brain stimulation in Parkinson's disease

AIM

Stereotactic localisation of brain targets for functional neurosurgery might be obtained with different neuroimaging sources. Magnetic resonance (MR) might be of particular interest for its high definition of the various brain structures; unfortunately, magnetic field distortion and inaccuracy in imaging reproduction constrain the use of MRI in stereotactic surgery.

METHODS

We present an experimental work devoted to the utilization of MRI in the targeting of the subthalamic nucleus for deep brain stimulation (DBS) in Parkinsonian patients.

RESULTS

Experimental data were obtained after PVC phantom and fixed human brain measurements of the stereotactic coordinates of specific basal ganglia structures. Intrinsic and external sources of error and imaging distortion have been carefully corrected. Afterwards, 36 patients, operated for DBS in the subthalamus for Parkinson's disease (PD), have been investigated. MRI targeting proved to be clinically successful; comparing anatomical and neurophysiological findings, MRI targeting scattered from the neurophysiological targeting in a minority of cases.

CONCLUSION

MRI targeting proved to be reliable for functional stereotactic surgery, pending careful and adequate quality control of the distortion and of the sources of error.

The reliability of measuring nursing clinical performance using a competency based assessment tool: a pilot study

The clinical performance of the novice nurse has been identified as problematic in the areas of medication administration, time management, and comfort and safety. In order to assess new graduate nurses' clinical competence in these areas, a forty four (44) item assessment tool was developed which was drawn from the Australian Nursing Council Inc. (ANCI) (1991) competency statements. A correlation descriptive design was used to determine the inter-rater reliability between assessors using this competency based tool. A pilot study utilising a convenience sample of 30 new graduate nurses were each assessed by two observers for a mean period of 127.5 minutes. Kappa coefficients were calculated to determine the level of agreement between the two observers. Very little rating agreement was found for individual items, however, there was no significant difference in the total competency scores between the two observers. The competency assessment tool has face validity and is internally consistent. However, inter-rater reliability for individual competency items was found to be poor.

The role of the ganglioside GD1a as a receptor for Sendai virus

The ganglioside GD1a, which serves as a receptor for Sendai virus, also affects lipid polymorphism as determined by 31P nuclear magnetic resonance. The ganglioside promotes the formation of isotropic structures in monomethyldioleoylphosphatidylethanolamine. GD1a also raises the bilayer to hexagonal phase transition temperature of this lipid. The effects of GD1a on the kinetics of viral fusion can be understood on the basis of its role in facilitating the binding of Sendai virus to target membranes as well as its effects on membrane physical properties. Fusion of Sendai virus with liposomes composed of egg phosphatidylethanolamine is particularly sensitive to the presence of ganglioside. In the absence of ganglioside no fusion is observed due to the absence of virus binding to the target membrane. Between 2 and 6 mol % GD1a in egg phosphatidylethanolamine liposomes there is a marked increase in the rate constant of binding of the virus to the liposome but a decrease in the fusion rate constant. The latter effect is found to be common to a number of other amphiphiles that raise the bilayer to hexagonal phase transition temperature. The ganglioside enhances virus binding to liposomes of all the compositions studied, but leakage rates and fusion rate constants are either unaffected or reduced. In the systems studied, the enhanced formation of isotropic structures in liposomes containing the ganglioside does not enhance the kinetics of the actual fusion reaction.