Blood ammonia levels after intravenous infusion of glycine solution with and without ethanol

Genetic architecture of cerebrospinal fluid and brain metabolite levels and the genetic colocalization of metabolites with human traits

Brain metabolism perturbation can contribute to traits and diseases. We conducted a genome-wide association study for cerebrospinal fluid (CSF) and brain metabolite levels, identifying 205 independent associations (47.3% new signals, containing 11 new loci) for 139 CSF metabolites, and 32 independent associations (43.8% new signals, containing 4 new loci) for 31 brain metabolites. Of these, 96.9% (CSF) and 71.4% (brain) of the new signals belonged to previously analyzed metabolites in blood or urine. We integrated the metabolite quantitative trait loci (MQTLs) with 23 neurological, psychiatric and common human traits and diseases through colocalization to identify metabolites and biological processes implicated in these phenotypes. Combining CSF and brain, we identified 71 metabolite-trait associations, such as glycerophosphocholines with Alzheimer's disease, O-sulfo-L-tyrosine with Parkinson's disease, glycine, xanthine with waist-to-hip ratio and ergothioneine with inflammatory bowel disease. Our study expanded the knowledge of MQTLs in the central nervous system, providing insights into human traits.

Glycine 1.5% for irrigation should be abandoned

BACKGROUND

Glycine 1.5% has long maintained a dominating role as an irrigating solution for monopolar transurethral resection of the prostate (TURP), as well as for certain other transurethral procedures.

MATERIALS AND METHODS

This review summarizes the findings of systematic experimental and clinical studies in which glycine 1.5% for irrigation was infused/absorbed and the outcome compared to at least one other irrigating fluid, including the isotonic saline used for bipolar TURP.

RESULTS

There were 11 studies in animals, 3 in volunteers and 6 in patients undergoing TURP. With only one exception, which is probably due to low power, these studies either show a poorer outcome after administration or absorption of glycine solution or else that glycine 2.2% is more toxic than glycine 1.5%. The poorer outcomes consisted of more tissue damage or higher mortality (animals) or more symptoms (volunteers and patients).

CONCLUSION

The safety of monopolar TURP would be improved by replacing glycine 1.5% with some other electrolyte-free fluid. The author argues that glycine 1.5% should be abandoned completely.

High-dose glycine treatment of refractory obsessive-compulsive disorder and body dysmorphic disorder in a 5-year period

This paper describes an individual who was diagnosed with obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD) at age 17 when education was discontinued. By age 19, he was housebound without social contacts except for parents. Adequate trials of three selective serotonin reuptake inhibitors, two with atypical neuroleptics, were ineffective. Major exacerbations following ear infections involving Group A β-hemolytic streptococcus at ages 19 and 20 led to intravenous immune globulin therapy, which was also ineffective. At age 22, another severe exacerbation followed antibiotic treatment for H. pylori. This led to a hypothesis that postulates deficient signal transduction by the N-methyl-D-aspartate receptor (NMDAR). Treatment with glycine, an NMDAR coagonist, over 5 years led to robust reduction of OCD/BDD signs and symptoms except for partial relapses during treatment cessation. Education and social life were resumed and evidence suggests improved cognition. Our findings motivate further study of glycine treatment of OCD and BDD.

Fluid absorption in endoscopic surgery

Fluid absorption is an unpredictable complication of endoscopic surgery. Absorption of small amounts of fluid (1-2 litre) occurs in 5-10% of patients undergoing transurethral prostatic resection and results in an easily overlooked mild transurethral resection (TUR) syndrome. Large-scale fluid absorption is rare but leads to symptoms severe enough to require intensive care. Pathophysiological mechanisms consist of pharmacological effects of the irrigant solutes, the volume effect of the irrigant water, dilutional hyponatraemia and brain oedema. Other less widely known factors include absolute losses of sodium by urinary excretion and morphological changes in the heart muscle, both of which promote a hypokinetic circulation. Studies in animals, volunteers and patients show that irrigation with glycine solution should be avoided. Preventive measures, such as low-pressure irrigation, might reduce the extent of fluid absorption but does not eliminate this complication. Monitoring the extent of absorption during surgery allows control of the fluid balance in the individual patient, but such monitoring is not used widely. However, the anaesthetist must be aware of the symptoms and be able to diagnose this complication. Treatment should be based on administration of hypertonic saline rather than on diuretics. New techniques, such as bipolar resectoscopes and vaporizing instead of resecting tissue, result in a continuous change of the prerequisites for fluid absorption and its consequences.