Chronic cerebellar stimulation in the monkey. Preliminary observations.

In a single monkey, the surface of the cerebellum was stimulated electrically for 205 hours with electrodes and parameter values similar to those currently used in humans for treatment of epilepsy. Im pedance of stimulating and nonstimulating control electrodes remained unchanged throughout an observation period of six months. Potentials evoked by cerebellar stimulation could be recorded from the cranium, providing a noninvasive technique of determining the level of current delivered to cerebellum. Examination of the implantation site showed marked meningeal thickening surrounding the stimulating electrodes. Such thickening was not observed surrounding a control set. Light and electron microscopical examination revealed severe loss of Purkinje cells in tissue near the stimulating electrodes. There was also a moderate loss in other parts of cerebellar cortex down to a depth of about 1 mm from the exposed surface. Biochemical analysis revealed metabolic abnormalities consistent with the morphologic evidence of widespread tissue damage.     

Broad QRS tachycardia: Electrocardiographic diagnosis and management

The diagnostic difficulties between supraventricular tachyarrhythmias with intraventricular conduction delay and ventricular tachycardia have challenged the physician since the first recording of a ventricular tachycardia by Lewis in 1909. The examples selected emphasize some of the diagnostic and therapeutic dilemmas of "broad QRS tachycardias" and their major differential features from abberrancy. Multiple simultaneous surface ECG leads are valuable in showing the direction of the initial activation forces of the QRS complexes, the frontal QRS axis and the configuration of the QRS in lead V1. Vagal maneuvers and intra-atrial or esophageal leads are very useful in demonstrating the underlying atrial rhythm and atrioventricular dissociation when present. In life-threatening situations, urgent therapy or D.C. cardioversion may be required before a definitive diagnosis has been established. In recent years electrode catheter techniques for the diagnosis, for arrhythmia induction and for the selection and assessment of the effectiveness of the antiarrhythmic drug therapy have been carried out in the management of recurrent broad QRS tachycardia. In view of the inherent risks with the use of this invasive technique, it should be restricted to a carefully selected number of patients with recurrent life-threatening dysrhythmias as suggested by Scheinman.     

Long-term surface stimulation of the cerebellum in the monkey. II. Electron microscopic and biochemical observations.

Phase and electron microscopy were used to study the effects of chronic intermittent or continuous stimulation applied to the surface of the cerebellum with bipolar platinum electrodes in monkeys. Damage under the anodes consisted of swelling of neuropil, variable loss of Purkinje cells, and a variable increase in fibrous glial processes. Under the cathode there was marked loss of Purkinje cells, thinning of the molecular layer, moderate swelling, occasional phagocytes with lipofuscin granules, and often an increase of fibrous glial processes. Despite the damage, normal appearing synaptic terminals remained in all layers under both anode and cathode, though sparser in fibrotic areas Gamma-aminobutyric acid (GABA) concentrations were decreased beneath the cathodes, reflecting the loss of Purkinje cells and other GABA-containing cells, and spermidine concentrations were increased in areas with increased fibrous glial processes.     

The Effect of the COVID-19 Pandemic on the Workload of an Adult Major Trauma Centre in Northern Ireland

Introduction:Based in Belfast, the Royal Victoria Hospital is the only Major Trauma Centre in Northern Ireland. Due to the COVID-19 pandemic, on 23rd March 2020, Northern Ireland was placed into ‘lockdown'' with the majority of the population advised to “stay at home”. The objective of this paper is to identify what effect the lockdown restrictions had on the workload of the Major Trauma Service at the Royal Victoria Hospital.Method:Patients were identified at the orthopaedic trauma meetings and from direct referral to the Major Trauma Service (MTS). Patients admitted and seen by the MTS from 23/03/20, the day lockdown was announced, to 29/05/20, when restrictions were partially lifted, were included in the analysis. Admissions data from this time period was then compared to admissions data from the same period in 2019 (23/03/19 - 29/05/19).Results:When comparing pre-lockdown and lockdown groups there was an overall decrease of 26% in admissions to the MTS (n=57 vs n=42). Road Traffic Accidents were reduced by 53% (n=31 vs n=15) and falls from >2m were reduced by 29% (n=21 vs n=15).Conclusion:Overall the number of admissions to the major trauma service was reduced during the lockdown period. A significant proportion of the reduction may be a result of social restrictions that reduced volume of traffic on Northern Irelands roads. Further study of future lockdowns and including admissions data of other MTCs in the UK would allow us to draw more robust conclusions.     

Blood components in neonatal medicine

During a six-month period, 552 infants were admitted to a level III Neonatal Intensive Care Unit (NICU) and four level II units. Of the 953 cross matches of blood components requested from the blood bank, 83% were administered. Forty-four percent of the infants received multiple blood transfusions from multiple blood donors (mean 3.9 donors, range two to 11). Thirty-one percent received multiple transfusions from only one donor. The mean total volume of blood given was 22.5 ml (range 3 to 120 ml), exclusive of blood used for exchange transfusions. Seventy percent of the blood components were given to infants weighing less than 2,500 gm, and 44% were given to infants weighing less than 1,500 gm. Hospitals having only level II units must have the same blood banking facilities as hospitals with level III units, since 21% of the infants given transfusion received the blood component while receiving level II care.     

Thermally-healable network solids of sulfur-crosslinked poly(4-allyloxystyrene)

Network polymers of sulfur and poly(4-allyloxystyrene), PAOS_x (x = percent by mass sulfur, where x is varied from 10–99), were prepared by reaction between poly(4-allyloxystyrene) with thermal homolytic ring-opened S₈ in a thiol-ene-type reaction. The extent to which sulfur content and crosslinking influence thermal/mechanical properties was assessed. Network materials having sulfur content below 50% were found to be thermosets, whereas those having >90% sulfur content are thermally healable and remeltable. DSC analysis revealed that low sulfur-content materials exhibited neither a T_g nor a T_m from −50 to 140 °C, whereas higher sulfur content materials featured T_g or T_m values that scale with the amount of sulfur. DSC data also revealed that sulfur-rich domains of PAOS₉₀ are comprised of sulfur-crosslinked organic polymers and amorphous sulfur, whereas, sulfur-rich domains in PAOS₉₉ are comprised largely of α-sulfur (orthorhombic sulfur). These conclusions are further corroborated by CS₂-extraction and analysis of extractable/non-extractable fractions. Calculations based on TGA, FT-IR, H₂S trapping experiments, CS₂-extractable mass, and elemental combustion microanalysis data were used to assess the relative percentages of free and crosslinked sulfur and average number of S atoms per crosslink. Dynamic mechanical analyses indicate high storage moduli for PAOS₉₀ and PAOS₉₉ (on the order of 3 and 6 GPa at −37 °C, respectively), with a mechanical T_g between −17 °C and 5 °C. A PAOS₉₉ sample retains its full initial mechanical strength after at least 12 pulverization-thermal healing cycles, making it a candidate for facile repair and recyclability.

Sulfur and a polystyrene derivative were combined to form thermally-healable and recyclable composite materials with dramatically increased structural integrity versus sulfur alone.