Abnormalities of vitamin B12 and folic acid metabolism--their influence on the nervous system

Clinical, Electrophysiological and Radiological Features of Nitrous Oxide-Induced Neurological Disorders

PURPOSE

We summarized the clinical manifestations, laboratory and electrodiagnostic characteristics and magnetic resonance imaging (MRI) findings of nitrous oxide (N₂O) abuse-induced neurological disorders.

PATIENTS AND METHODS

We retrospectively reviewed 33 patients with N₂O abuse-induced neurological disorders and reported their demographic data, clinical manifestations, laboratory examinations, nerve conduction studies, together with spinal and brain MRI.

RESULTS

The most frequent clinical manifestations included numbness and weakness in the extremities and unspecified gait disturbance. Low serum vitamin B₁₂ levels were found in 9 patients, and high homocysteine levels were noted in 27 patients. Nerve conduction studies showed a sensory-motor neuropathy. Sixteen patients showed bilateral high-intensity T2 signal within the posterior column on spinal MRI, and four patients showed cerebral white matter lesions on brain MRI.

CONCLUSION

N₂O abuse has become a significant public health problem because of the severe neurological disorders related to chronic abuse. Clinical physicians should be aware of the toxic effects of N₂O.

Predicting neurological Adverse Drug Reactions based on biological, chemical and phenotypic properties of drugs using machine learning models

Adverse drug reactions (ADRs) have become one of the primary reasons for the failure of drugs and a leading cause of deaths. Owing to the severe effects of ADRs, there is an urgent need for the generation of effective models which can accurately predict ADRs during early stages of drug development based on integration of various features of drugs. In the current study, we have focused on neurological ADRs and have used various properties of drugs that include biological properties (targets, transporters and enzymes), chemical properties (substructure fingerprints), phenotypic properties (side effects (SE) and therapeutic indications) and a combinations of the two and three levels of features. We employed relief-based feature selection technique to identify relevant properties and used machine learning approach to generated learned model systems which would predict neurological ADRs prior to preclinical testing. Additionally, in order to explain the efficiency and applicability of the models, we tested them to predict the ADRs for already existing anti-Alzheimer drugs and uncharacterized drugs, respectively in side effect resource (SIDER) database. The generated models were highly accurate and our results showed that the models based on chemical (accuracy 93.20%), phenotypic (accuracy 92.41%) and combination of three properties (accuracy 94.18%) were highly accurate while the models based on biological properties (accuracy 82.11%) were highly informative.

Serum vitamin B 12 levels in Indian psychiatric patients

It is known that pernicious anaemia is sometimes associated with mental symptoms which improve following vitamin B12 therapy (Eilenberg, 1960; Holmes, 1956; Smith, 1960). Further, it has been pointed out that such mental symptoms can occur years before the development of anaemia and no definite relationship exists between them and the severity of anaemia (Smith, 1960). Cases have been described with a variety of psychiatric symptoms and low serum vitamin B12 levels without any neurological manifestation or abnormality of peripheral blood and bone marrow. Since pernicious anaemia is due to vitamin B12 deficiency it is suspected that B12 deficiency is responsible for the mental symptoms, and serum B12 assays have been advocated routinely in psychiatric patients (Strachan and Henderson, 1965; Hunter and Matthews, 1965).