Catheter Induced Distal Intra-Hisian Right Bundle Branch Block in a Patient with Persistent Proximal Intra-Hisian Complete A-V Block

We describe a patient with complete intra-Hisian A-V block and narrow QRS who developed catheter-induced right bundle branch block during an electrophysiological study. Selective His bundle pacing was performed during complete intra-Hisian A-V block and right bundle branch block pattern; the distal His bundle pacing normalized the QRS complex, while a more proximal His bundle stimulation showed a right bundle branch block configuration with the persistence of the proximal intra-Hisian lesion responsible for the complete A-V block. These electrophysiological findings suggest that the catheter-induced right bundle branch block in our patient was due to a focal lesion in the distal part of the main His bundle. To our knowledge, this is the first report of documented multilevel lesions within the His bundle in man.     

The relationship between sleep and epilepsy: the effect on cognitive functioning in children

Aim The purpose of this review was to examine the possible pathophysiological links between epilepsy, cognition, sleep macro‐ and microstructure, and sleep disorders to highlight the contributions and interactions of sleep and epilepsy on cognitive functioning in children with epilepsy. Method PubMed was used as the medical database source. No language restriction was placed on the literature searches, and citations of relevant studies in the paediatric age range (0–18y) were checked. Studies including a mixed population but with a high percentage of children were also considered. Results The searches identified 223 studies. One reviewer scanned these to eliminate obviously irrelevant studies. Three reviewers scanned the remaining 128 studies and their relevant citations. The review showed that several factors could account for the learning impairment in children with epilepsy: aetiology, electroencephalographic (EEG) discharges, and persistence and circadian distribution of seizures, etc. EEG discharges may affect cognition and sleep, even in the absence of clinical or subclinical seizures. The sleep deprivation and/or sleep disruption affect the neurophysiological and neurochemical mechanisms important for the memory–learning process, but also influence the expression of EEG discharges and seizures. Learning and memory consolidation can take place over extended periods, and sleep has been demonstrated to play a fundamental role in these processes through neuroplastic remodelling of neural networks. Epilepsy and EEG paroxysms may affect sleep structure, interfering with these physiological functions. Interpretation Improvement in the long‐term cognitive–behavioural prognosis of children with epilepsy requires both good sleep quality and good seizure control. The antiepileptic drug of choice should be the one that interferes least with sleep structure and has the best effect on sleep architecture – thus normalizing sleep instability, especially during non‐rapid eye movement sleep.     

Cognitive visual dysfunctions in preterm children with periventricular leukomalacia

Aim  Cognitive visual dysfunctions (CVDs) reflect an impairment of the capacity to process visual information. The question of whether CVDs might be classifiable according to the nature and distribution of the underlying brain damage is an intriguing one in child neuropsychology.
Method  We studied 22 children born preterm (12 males, 10 females; mean age at examination 8y, range 6–15y; mean gestational age 30wks, range 28–36wks) with periventricular leukomalacia, spastic diplegia, normal intelligence (mean Full-scale IQ 84; mean Verbal IQ 97; mean Performance IQ 74), and normal visual acuity, focusing on higher visual functions. Brain magnetic resonance images (MRI) were analysed to establish the presence of lesions along the primary optic pathway, in the occipitoparietal and occipitotemporal regions.
Results  Most children displayed an uneven cognitive profile, with deficits in visual object recognition, visual imagery, visual–spatial skills, and visual memory, and sparing of visual associative abilities, non-verbal intelligence, and face and letter recognition. Conventional brain MRI did not document major alterations of parietal and temporal white matter, or cortical alteration of areas involved in visual associative functions.
Interpretation  We suggest a widespread involvement of higher visual processing systems, involving both the ventral and dorsal streams, in preterm children with periventricular leukomalacia. The lack of major alterations on conventional MRI does not exclude the possibility of malfunctioning of higher visual processing systems, expressing itself through discrete CVDs. Possible mechanisms underlying these neuropsychological deficits are discussed.     

Hyperosmolar coma due to exclusive glucose accumulation: Recognition and computations

Aim: To avoid electrolyte derangements during correction of hyperosmolar coma (HC), PNa_PREDICTED at the end of correction is presently estimated from plasma glucose (P_G, mM/L). When the rise in plasma osmolality (Posm) is entirely due to glucose addition (G_A, mM) to the extracellular volume (ECV), this PNa prediction can be improved by correctly estimating G_A and any associated water loss (ΔV), while excluding any concomitant Na loss (ΔNa). Methods: Indicating with ₀ the normal conditions, with ₁ the HC, establishes an exclusive G_A accumulation. We derived the equations for computing G_A, ΔV and PNa_PREDICTED. Computer simulations of HC were performed by adding the known G_A while subtracting the known ΔV and ΔNa in different combinations, obtaining exact values of PNa₁ and . Applying our formulas, we recognized and discarded all cases with concomitant ΔNa, and we computed G_A, ΔV and PNa_PREDICTED from PNa₁ and , as if they had been measured in patients. We extended these same calculation algorithms to 68 patients with HC. Results: In computer simulations, true and calculated G_A, ΔV and PNa_PREDICTED were identical, such that regression and correlation coefficients were 1 (P < 0.0001). Out of the 68 patients recruited, 13 fulfilled the boundary conditions of an exclusive G_A addition. The true values, obtained by balance studies performed on these patients, were not different from and significantly correlated with the calculated data (R² = 0.99, P < 0.001). Conclusion: Our new model system for HC and the new formulas improve to near exactness the accuracy in estimating PNa_PREDICTED, helping the physician to avoid unwanted electrolyte derangements during treatment.     

THE SPECTRUM OF 67-kD LAMININ RECEPTOR EXPRESSION IN BREAST CARCINOMA PROGRESSION

Laminin is a glycoprotein of the basement membrane (BM), involved in a variety of normal and pathological cellular events including tumour invasion and metastasis. Cells bind laminin through different types of receptor. The 67-kD laminin receptor (67LR) is a cell-surface protein which binds laminin with high affinity. 67LR expression has been shown to increase in neoplastic cells, compared with normal tissues, and 67LR seems to play an important role during the first steps of neoplastic progression. In this study, 67LR expression was analysed during the morphological phases of breast cancer progression from normal tissue to invasive carcinoma. A total of 506 formalin-fixed, paraffin-embedded normal breast structures and lesions were stained by immunohistochemistry using the MLuC5 monoclonal antibody, which is specific for 67LR. The results show that in normal breast and in any kind of breast lesion, myoepithelial and endothelial cells express 67LR. While 67LR is not seen in the epithelium of normal breast, cysts, adenosis, and benign tumours, it is expressed in the epithelial cells of several hyperplasias and carcinomas in situ, both ductal and lobular, as well as in all invasive carcinomas. The 67LR-positive cell subpopulation expands from hyperplastic lesions to invasive carcinoma, suggesting that 67LR could be related to the induction and progression of breast cancer. © 1997 John Wiley & Sons, Ltd.     

A Prospective, Randomized, Comparison in Patients Between a Pectoral Unipolar Defibrillation System and That Using an Additional Inferior Vena Cava Electrode

The decrease of defibrillation energy requirement would render the currently available transvenous defibrillator more effective and favor the device miniaturization process and the increase of longevity. The unipolar defibrillation systems using a single RV electrode and the pectoral pulse generator titanium shell (CAN) proved to be very efficient. The addition of a third defibrillating electrode in the coronary sinus did not prove to offer advantages and in the superior vena cava showed only a slight reduction of the defibrillation threshold (DFT). The purpose of this study was to determine whether the defibrillation efficacy of the single lead unipolar transvenous system could be improved by adding an electrode in the inferior vena cava (IVC). In 17 patients, we prospectively and randomly compared the DFT obtained with a single lead unipolar system with the DFT obtained using an additional of an IVC lead. The RV electrode, Medtronic 6936, was used as anode (first phase of biphasic) in both configurations. A 108 cm2 surface CAN, Medtronic 7219/7220 C, was inserted in a left submuscular infraclavicular pocket and used as cathode, alone or in combination with IVC, Medtronic 6933. The superior edge of the IVC coil was positioned 2-3 cm below the right atrium-IVC junction. Thus, using biphasic 65% tilt pulses generated by a 120 microF external defibrillator, Medtronic D.I.S.D. 5358 CL, the RV-CAN DFT was compared with that obtained with the RV-CAN plus IVC configuration. Mean energy DFTs were 7.8 +/- 3.6 and 4.8 +/- 1.7 J (P < 0.0001) and mean impedance 65.8 +/- 13 O and 43.1 +/- 5.5 O (P < 0.0001) with the RV-CAN and the IVC configuration, respectively. The addition of IVC significantly reduces the DFT of a single lead active CAN pectoral pulse generator. The clinical use of this biphasic and dual pathway configuration may be considered in patients not meeting implant criteria with the single lead or the dual lead RV-superior vena cava systems. This configuration may also prove helpful in the use of very small, low output ICDs, where the clinical impact of ICD generator size, longevity, and related cost may offset the problems of dual lead systems.     

Effects of bromocriptine on adenylate cyclase and phosphodiesterase activities of rat striatum

The activity of 2-bromo-α-ergokryptine (bromocriptine) (5 mg kg^?1, i.p.) on adenylate cyclase and on phosphodiesterase (PDE I-PDE II) of rat striatum, has been examined both in vitro and in vivo. In vitro and in vivo bromocriptine stimulated adenylate cyclase activity, but reduced the stimulating effect of dopamine on adenylate cyclase activity. Bromocriptine showed a dose-dependent biphasic action on phosphodiesterases in vitro while in vivo it stimulated them. The results obtained proved bromocriptine to have an agonist-antagonist action at striatal dopamine receptor level, with a relevant effect on the cAMP system.