Interhemispheric influences on area 19 of the cat

Summary Anatomical studies have shown an extensive network of homotopic and heterotopic interhemispheric connections in area 19 of the cat visual cortex (Segraves and Rosenquist 1982a; 1982b). We have investigated their functional organization by recording visual responses in area 19 of cats following a midsagittal section of the optic chiasm. This operation interrupts all crossed optic fibers coming both from the nasal and the temporal retinae; as a result, each hemisphere receives optic fibers only from the lateral hemiretina of the ipsilateral eye which conveys information from the contralateral visual field. Visual information transmitted to the same hemisphere from the contralateral retina and the ipsilateral visual field must be attributed to an indirect, interhemispheric pathway. We found that a rather high proportion of neurons (31.8%) in area 19 of seven split-chiasm cats responded to visual stimuli presented to the contralateral eye. 1 — All neurons receiving this interhemispheric activation were also driven by the ipsilateral eye via an intrahemispheric pathway. 2 — The property of binocularity was significantly related to the visuotopic map in that both receptive fields of each binocular neuron adjoined or were in the immediate vicinity of the vertical meridian. 3 — Due to the small size of receptive fields in area 19, the contribution of the interhemispheric pathway to the representation of the visual field is rather limited and it is certainly less extensive than that predicted by anatomical studies. The representation of the ipsilateral visual field in area 19 of intact cats, as assessed electrophy-siologically, was comparable to that found in split-chiasm cats. Recordings in areas 17–18 of split-chiasm cats showed that the visual field represented through the corpus callosum in these visual areas is certainly not less and probably more, extensive than that found in area 19. The results support the conclusion that the relation to the vertical meridian and the receptive field size can explain the organization of the interhemispheric connections in the visual areas studied so far.     

An Observational Study of the Effect of Levodopa–Carbidopa Intestinal Gel on Activities of Daily Living and Quality of Life in Advanced Parkinson’s Disease Patients

Introduction

Continuous delivery of levodopa–carbidopa intestinal gel (LCIG) by percutaneous endoscopic gastrojejunostomy (PEG-J) in advanced Parkinson’s disease (PD) patients reduces variability in plasma levels, providing better control of motor fluctuations (“on” and “off” states). The MONOTREAT study assessed the effect of LCIG on activities of daily living, motor and non-motor symptoms, and quality of life in advanced PD patients.

Methods

This prospective, observational study included patients with advanced, levodopa-responsive PD with either 2–4 h of “off” time or 2 h of dyskinesia daily. Patients received LCIG via PEG-J for 16 h continuously. Effectiveness was assessed using Unified PD Rating Scale parts II and III, the Non-Motor Symptom Scale, and the PD Questionnaire-8.

Results

The mean (SD) treatment duration was 275 (157) days. Patients experienced significant improvement from baseline in activities of daily living at final visit (p < 0.05) as well as at months 3 and 6 (p < 0.0001). Patients also experienced significant improvements from baseline in quality of life and non-motor symptoms at all time points (p < 0.001 for all). Specifically, patients manifested significant improvements in mean change from baseline at every study visit in five of nine non-motor symptom score domains: sleep/fatigue, mood/cognition, gastrointestinal tract, urinary, and miscellaneous. One-third of patients (32.8%) experienced an adverse event; 21.9% experienced a serious adverse event; 11.1% discontinued because of an adverse event.

Conclusion

This study demonstrated significant and clinically relevant improvements in measures of activities of daily living, quality of life, and a specific subset of non-motor symptoms after treatment with LCIG.

Funding

AbbVie Inc.

     

Incidence of low central venous oxygen saturation during unplanned admissions in a multidisciplinary intensive care unit: an observational study

Introduction  

It has been shown that early central venous oxygen saturation (ScvO₂)-guided optimization of hemodynamics can improve outcome in septic patients. The early ScvO₂ profile of other patient groups is unknown. The aim of this study was to characterize unplanned admissions in a multidisciplinary intensive care unit (ICU) with respect to ScvO₂ and outcome.     

Lung ultrasonography for assessment of oxygenation response to prone position ventilation in ARDS

Purpose

Prone position (PP) improves oxygenation and outcome of acute respiratory distress syndrome (ARDS) patients with a PaO₂/FiO₂ ratio <150 mmHg. Regional changes in lung aeration can be assessed by lung ultrasound (LUS). Our aim was to predict the magnitude of oxygenation response after PP using bedside LUS.

Methods

We conducted a prospective multicenter study that included adult patients with severe and moderate ARDS. LUS data were collected at four time points: 1 h before (baseline) and 1 h after turning the patient to PP, 1 h before and 1 h after turning the patient back to the supine position. Regional lung aeration changes and ultrasound reaeration scores were assessed at each time. Overdistension was not assessed.

Results

Fifty-one patients were included. Oxygenation response after PP was not correlated with a specific LUS pattern. The patients with focal and non-focal ARDS showed no difference in global reaeration score. With regard to the entire PP session, the patients with non-focal ARDS had an improved aeration gain in the anterior areas. Oxygenation response was not associated with aeration changes. No difference in PaCO₂ change was found according to oxygenation response or lung morphology.

Conclusions

In ARDS patients with a PaO₂/FiO₂ ratio ≤150 mmHg, bedside LUS cannot predict oxygenation response after the first PP session. At the bedside, LUS enables monitoring of aeration changes during PP.

     

Massive intrahepatic haemorrhage responsible for an inferior vena cava syndrome: an exceptional complication of hepatocellular carcinoma

Intralesional massive haemorrhage responsible for inferior vena cava syndrome is a very rare complication of hepatocellular carcinoma. A 36-year-old man with no past medical history was referred to hospital for abdominal pain with clinical and biological signs of internal bleeding. An abdominal CT scan showed a huge right liver mass, with regular margins and a fluid content, indicating a large intratumoral haemorrhage complicating hepatocellular carcinoma. Due to haemodynamic stability and the signs of inferior vena cava compression conservative management was chosen prior to surgical treatment of the tumour. Three months later, the huge liver mass remained unchanged but the inferior vena cava syndrome had decreased and the patient's condition improved. After evaluation of liver function and the extent of the tumour, a surgical procedure was performed via a subcostal incision with midline extension and sternotomy to control the intrapericardial inferior vena cava and perform a veno-venous bypass with the technique used for orthotopic liver transplantation. Then, right hepatectomy (segments V to VIII) was performed with an anterior approach. The postoperative course was uneventful. This two-step strategy allowed successful surgery for this rare complication of a hepatocellular carcinoma on a normal liver and could be recommended for the management of any unruptured intratumoral haemorrhages.     

Different effects of high and low shear stress on platelet-derived growth factor isoform release by endothelial cells: consequences for smooth muscle cell migration

In the present study, we analyzed the effect of conditioned media (CM) from bovine aortic endothelial cells exposed to laminar shear stress (SS) of 5 dyne/cm2 (SS5) or 15 dyne/cm2 (SS15) for 16 hours on smooth muscle cell (SMC) migration. In response to CM from bovine aortic endothelial cells exposed to SS5 (CMSS5) and SS15 (CMSS15), migration was 45 +/- 5.5 and 30 +/- 1.5 cells per field, respectively (P<0.05). Similar results were obtained with SS of 2 versus 20 dyne/cm2 and also when SS of 5 and 15 dyne/cm2 lasted 24 hours. Platelet-derived growth factor (PDGF)-AA levels in CMSS5 and CMSS15 were 9 +/- 7 and 18 +/- 5 ng/10(6) cells for 16 hours, respectively (P<0.05); PDGF-BB levels in CMSS5 and CMSS15 were 38 +/- 10 and 53 +/- 10 ng/10(6) cells for 16 hours, respectively (P<0.05). PDGF receptor alpha (PDGFRalpha) and PDGF receptor beta (PDGFRbeta) in SMCs were phosphorylated by CMSS15>CMSS5. In response to CMSS15, a neutralizing antibody against PDGF-AA enhanced SMC migration to a level comparable to that of CMSS5; in contrast, antibodies against PDGF-BB abolished SMC migration. Transfection of SMCs with a dominant-negative PDGFRalpha or PDGFRbeta increased or inhibited, respectively, SMC migration in response to CMSS15. Overexpression of wild-type PDGFRalpha inhibited SMC migration in response to CMSS5, CMSS15, or recombinant PDGF-BB (P<0.001). These results suggest that the ability of high SS to inhibit arterial wall thickening in vivo may be related to enhanced activation of PDGFRalpha in SMCs by PDGF isoforms secreted by the endothelium.     

Increased temporal dispersion of myocardial repolarization in myotonic dystrophy type 1: beyond the cardiac conduction system

Objectives

To assess ventricular dysfunction and ventricular interaction after repair of Tetralogy of Fallot (ToF) employing echocardiography speckle-tracking and cardiac magnetic resonance imaging (CMR).

Background

Severe pulmonary regurgitation and right ventricular (RV) dysfunction are common after repair of ToF and may also affect the shape and function of the left ventricle (LV). Recent studies suggest that LV dysfunction may be of particular prognostic value.

Methods and results

Twenty-one consecutive adults with repaired ToF (15 male, mean age 38 ± 11 years, 7 with severe PR) underwent a comprehensive echocardiographic exam including speckle-tracking analysis, CMR and cardiopulmonary exercise testing. Twenty-one subjects without relevant heart disease served as controls. Echocardiographically measured RV diameters correlated with RV volumes obtained from CMR (r = 0.63; p = 0.006). In addition, a close correlation was found between RV and LV function on CMR (r = 0.74, p = 0.002), speckle-tracking LV and RV peak longitudinal 2D strain (r = 0.66, p = 0.003) and mitral and tricuspid annular plain systolic excursion (r = 0.71, p = 0.0003). While LV ejection fraction was normal in the majority of patients and not different from controls, LV longitudinal strain was significantly reduced in ToF patients (− 16.5 ± 3.3 vs. -20.5 ± 2.7%, p = 0.0001).

Conclusion

Left and right ventricular function both by CMR and speckle-tracking is interrelated in adults with repaired ToF. Despite normal LV ejection fraction, 2D longitudinal strain is significantly reduced in ToF patients, suggesting subclinical LV myocardial damage. Considering the potential prognostic value of LV dysfunction in ToF, this measurement may gain importance and should be included in future outcome studies.     

Usefulness of atherogenic dyslipidemia for predicting cardiovascular risk in patients with angiographically defined coronary artery disease

The identification of factors contributing to residual cardiovascular risk is important to improve the management of patients with established coronary artery disease (CAD). This study was conducted to assess the predictive value of atherogenic dyslipidemia (defined as high triglycerides and low high-density lipoprotein [HDL] cholesterol) for long-term outcomes in patients with CAD. In 284 patients (238 men, 46 women; mean age at baseline 59.2 +/- 8.9 years) with coronary stenosis (>50% in > or =1 vessel), the presence of atherogenic dyslipidemia was prospectively associated with the incidence of major adverse cardiovascular events (MACEs) during a median follow-up of 7.8 years. MACEs were defined as cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, the recurrence of angina, and revascularization procedures. MACEs were observed in 111 (39.1%) patients with CAD. MACEs occurred more frequently in patients with atherogenic dyslipidemia (50.9%) than in those with isolated low HDL cholesterol or high triglycerides (33.0%) or with normal HDL cholesterol and triglyceride concentrations (29.2%) (p <0.01 for trend). Kaplan-Meier survival analysis showed a decrease in event-free survival in patients with compared with those without atherogenic dyslipidemia (log-rank p = 0.006). Patients with atherogenic dyslipidemia presented with increased plasma concentrations of remnants, denser low-density lipoprotein, more atherogenic HDL particles, and insulin-resistant status. After adjustment for potential confounding variables, the magnitude of increased risk associated with atherogenic dyslipidemia was 1.58 (95% confidence interval 1.12 to 2.21, p = 0.008). In conclusion, these data provide evidence that atherogenic dyslipidemia is an independent predictor of cardiovascular risk in patients with CAD, even stronger than isolated high triglycerides or low HDL cholesterol.