Microsurgical anatomy of VII and VIII cranial nerves and related arteries in the cerebellopontine angle

Summary The relationships of VII and VIII cranial nerves and related arteries are reviewed in 26 preparations by microdissection techniques. These vessels may be grouped in large (AICA, PICA), medium (LA, SA, CSA, RPI) and small calibre (vasa nervorum, radicullar and medullar branches). The importance of these structures in acoustic neuroma surgery, vestibular neurectomy and cross-compression syndromes is discussed. Vascular loops and elongated arteries are normal structures present at birth.This work was supported by a grant from the AJ Roemmers Foundation     

The QT interval during wake and sleep in patients with ventricular arrhythmias

Eight patients with frequent ventricular ectopy underwent continuous electrocardiographic (ECG) and polygraphic monitoring for 4 days. A complex protocol consisted of normal day-night, activity-nonactivity, cycles for 48 h (nine patients); followed by a 24-h awake bedrest; and finally by a very delayed sleep and inactivity phase in the morning before returning to a normal day-night cycle (eight patients only). ECG tracings showed that the QT intervals during rapid eye movement sleep and nonrapid eye movement sleep increased significantly when compared with active wakefulness. The Bazett's corrected QT (QTc) interval also increased from active wakefulness to rapid eye movement sleep and nonrapid eye movement sleep. Adjusted mean QT intervals computed using the RR [corrected] interval as a covariate were significantly longer during non-rapid-eye-movement (407 ms) and rapid-eye-movement (408 ms) sleep than during active wakefulness (386 ms). The RR-adjusted mean QT intervals during inactive wake were also longer (400 ms) but this clear trend did not reach statistical significance (p = 0.08). Although prolongation of the QT interval during sleep reflects inactivity that may be related to withdrawal of sympathetic tone, we postulate that sleep per se also has an effect on the interval.     

KChIP1 and frequenin modify shal-evoked potassium currents in pyloric neurons in the lobster stomatogastric ganglion

The transient potassium current (I(A)) plays an important role in shaping the firing properties of pyloric neurons in the stomatogastric ganglion (STG) of the spiny lobster, Panulirus interruptus. The shal gene encodes I(A) in pyloric neurons. However, when we over-expressed the lobster Shal protein by shal RNA injection into the pyloric dilator (PD) neuron, the increased I(A) had somewhat different properties from the endogenous I(A). The recently cloned K-channel interacting proteins (KChIPs) can modify vertebrate Kv4 channels in cloned cell lines. When we co-expressed hKChIP1 with lobster shal in Xenopus oocytes or lobster PD neurons, they produced A-currents resembling the endogenous I(A) in PD neurons; compared with currents evoked by shal alone, their voltage for half inactivation was depolarized, their kinetics of inactivation were slowed, and their recovery from inactivation was accelerated. We also co-expressed shal in PD neurons with lobster frequenin, which encodes a protein belonging to the same EF-hand family of Ca(2+) sensing proteins as hKChIP. Frequenin also restored most of properties of the shal-evoked currents to those of the endogenous A-currents, but the time course of recovery from inactivation was not corrected. These results suggest that lobster shal proteins normally interact with proteins in the KChIP/frequenin family to produce the transient potassium current in pyloric neurons.     

Prenatal diagnosis and family studies in a case of propionicacidaemia

In a family with a history of two neonatal deaths, propionicacidaemia was diagnosed retrospectively from stored plasma as the cause of the second death during the mother's next pregnancy. Amniocentesis was performed and a culture of amniotic cells was assayed for propionyl CoA carboxylase activity. The absence of any detectable propionyl CoA carboxylase activity allowed the prenatal diagnosis of propionicacidaemia to be made. Treatment with biotin and a modified aminoacid diet was started in the immediate postnatal period. Investigation of propionyl CoA carboxylase in leucocytes from the parents, siblings and other relations of the patient failed to demonstrate intermediate enzyme activities in even the parents, who were presumably heterozygotes for this condition.     

Serum Fc gamma-receptor-like molecules in primary biliary cirrhosis: a possible immunoregulatory mechanism.

Functionally active Fc gamma-receptor-like molecules were isolated from normal human serum by affinity chromatography and shown to have an apparent molecular weight (MW) of approximately 60,000 as assessed by SDS-polyacrylamide gel electrophoresis. These low MW Fc gamma-receptor-like molecules were found to be significantly reduced in whole serum, and in all of six serum fractions, obtained from patients with primary biliary cirrhosis (PBC). A high MW IgG-binding factor, with partial Fc gamma-receptor-like activity, was also found in PBC serum. This factor was also observed to a lesser extent in normal serum. Detailed analysis of this factor suggests that it is a large macromolecule consisting of antigen (unknown). IgG class antibody and 60K Fc gamma-receptor-like molecules. Binding of serum Fc gamma R-like molecules to immune complexes may account for the apparent reduction in Fc gamma-receptor-like activity observed in whole PBC serum. These macromolecules may play an important role in immunoregulation.     

Effects of a gastric implant on body weight and gastrointestinal hormones in cafeteria diet obese rats

In order to evaluate the effectiveness of a gastric implant in an animal model of dietary obesity, silicone implants (2.5 ml) were inserted into the stomachs of male rats maintained on a chow or "cafeteria" diet. At the time of implantation, the cafeteria fed rats weighed 14% more than chow fed controls. Overweight cafeteria fed animals lost weight in response to the gastric implant, whereas control chow fed animals did not. Both implant groups had significant increases in stomach weights in contrast to sham implant groups, but the increase was much less in the cafeteria diet group. The fasting plasma levels of the gastrointestinal hormones, gastrin and pancreatic polypeptide, and oxytocin (a marker of vagal afferent function) were measured by radioimmunoassay. Cafeteria fed sham or implanted animals had significantly higher fasting levels of plasma oxytocin and gastrin, and significantly lower plasma levels of pancreatic polypeptide than the chow fed groups. These studies demonstrate that the gastric implant has more effect on weight in overweight animals on a palatable mixed diet, perhaps related to both mechanical and neural factors.     

Substance P and somatostatin content and transport in the vagus and sciatic nerves of the aging Fischer 344 rat

The two widely distributed neuropeptides, substance P (SP) and somatostatin (SS), are synthesized in cell bodies of the sensory ganglia of the vagus and sciatic nerves and transported bidirectionally toward the central nervous system and sites of sensory innervation. In this study, the content of both peptides was measured in the vagus and sciatic nerves of Fischer 344 rats aged 4, 12 and 25 months. In addition, as an indicator of biosynthesis within the sensory ganglia, the quantity of neuropeptide transported during 22 hours in a peripheral orthograde direction was measured using the ligation technique in animals age 12, 18 and 25 months. The content and transported quantity of SP was unchanged or slightly increased in both nerves as a function of age. Somatostatin content was unchanged and transport increased in the vagus of older rats. In contrast, in the sciatic nerve, SS content was reduced by more than 30% in older rats (p less than 0.01); transported somatostatin was proportionately reduced (p less than 0.05). These findings demonstrate that neuropeptide levels in the sensory vagus are not reduced as a function of age. Somatostatinergic dorsal root ganglion neurons may be selectively vulnerable in the aging Fischer rat.     

Child psychiatry: one nation

This essay discusses the position of child psychiatry as a subspecialty in Canada today. Proceeding from a review of a paper written by Dr. Quentin Rae-Grant in 1970 "Adult and Child Psychiatry--One or Two Nations?" the author, using the concept of a nation as a metaphor, explores the evolution of child psychiatry as a subspecialty in Canada. The history of child psychiatry in Canada is reviewed briefly; from its early beginnings to an increased understanding of its uniqueness as a subspecialty, finally through to the formation of the Canadian Academy of Child Psychiatry in 1980. The essay stresses the mutuality of our dependence on the Canadian Psychiatric Association. The author emphasizes our mutual dependence on the greater organizational body of psychiatrists, and encourages a greater participation of child psychiatrists within the Canadian Psychiatric Association. The author also emphasizes the need to have a closer relationship with the Canadian Paediatric Society. In addition, the author discusses in some detail the more complex and controversial relationship between child psychiatry and the Royal College of Physicians and Surgeons of Canada. Finally the author emphasizes the importance of a close working relationship with the American Academy of Child and Adolescent Psychiatry. All of these relationships are emphasized in terms of mutual dependence.