The structure-AChE inhibitory activity relationships study in a series of pyridazine analogues

The structure-activity relationships (SAR) are investigated by means of the Electronic-Topological Method (ETM) followed by the Neural Networks application (ETM-NN) for a class of anti-cholinesterase inhibitors (AChE, 53 molecules) being pyridazine derivatives. AChE activities of the series were measured in IC(50) units, and relative to the activity levels, the series was partitioned into classes of active and inactive compounds. Based on pharmacophores and antipharmacophores calculated by the ETM-software as sub-matrices containing important spatial and electronic characteristics, a system for the activity prognostication is developed. Input data for the ETM were taken as the results of conformational and quantum-mechanics calculations. To predict the activity, we used one of the most well known neural networks, namely, the feed-forward neural networks (FFNNs) trained with the back propagation algorithm. The supervised learning was performed using a variant of FFNN known as the Associative Neural Networks (ASNN). The result of the testing revealed that the high ETM's ability of predicting both activity and inactivity of potential AChE inhibitors. Analysis of HOMOs for the compounds containing Ph1 and APh1 has shown that atoms with the highest values of the atomic orbital coefficients are mainly those atoms that enter into the pharmacophores. Thus, the set of pharmacophores and antipharmacophores found as the result of this study forms a basis for a system of the anti-cholinesterase activity prediction.

Reversible myelopathy with vitamin B12 deficiency

Vitamin B12 deficiency causes haematological, gastrointestinal, psychiatric and neurological diseases. Subacute combined degeneration (SCD) of the spinal cord, characterised by degeneration of the lateral and posterior columns, is often found due to vitamin B12 deficiency. We report SCD occurring in a 57-year-old man who presented with a 2.5-month history of gradually progressing tingling in the fingers and toes and neck ache. Laboratory data revealed vitamin B12 deficiency and magnetic resonance (MR) imaging of the cervical spinal cord demonstrated abnormal hyperintense signal changes on T2-weighted imaging of the posterior columns. In our case, follow-up MR imaging findings correlated well with clinical outcome after treatment with vitamin B12 supplements. Neurological symptoms in vitamin B12 deficiency are frequent. Early spinal MR imaging assists in the early diagnosis and treatment of the disease.

The Sensitivity of Clinical Diagnostic Methods in the Diagnosis of Diabetic Neuropathy

This study assessed the sensitivity of various methods for the clinical diagnosis of diabetic peripheral neuropathy. A total of 147 randomly selected patients with diabetes mellitus and 65 age- and sex-matched healthy controls were evaluated by various clinical (the neuropathy symptom score [NSS], the neuropathy disability score [NDS], vibration perception thresholds [VPTs], Tinel's sign and Phalen's sign), laboratory (fasting plasma glucose and glycosylated haemoglobin levels) and electrophysiological (nerve conduction studies, H-reflex and F-wave measurements) methods. In the patient group, 8.2% had an abnormal NSS, 28.5% had a positive Phalen's sign, 32.6% had a positive Tinel's sign, 42.8% had an abnormal VPT and 57.1% had an abnormal NDS. Significant correlations were found between electrophysiologically confirmed neuropathy and the two provocation tests and abnormal VPTs. In conclusion, assessment with a complete neurological examination and standard electrophysiological tests is very important for the diagnosis of diabetic peripheral neuropathy and the prevention of morbidity in patients with or without symptoms.

Electron-topological investigation of the structure-antitumor activity relationship of thiosemicarbazone derivatives

In the frameworks of the electron-topological method (ETM) the structure-antitumor activity relationship was investigated for a series of thiosemicarbazone derivatives. The series included 70 compounds. Conformational analysis and quantum-chemical calculations were carried out for each compound. The revealed activity feature showed a satisfactory description of the class of active compounds according to two different parameters P and alpha estimating the probabilities of the feature realization in the class of active compounds (they are equal to 0.94 and 0.86, correspondingly). The results of testing demonstrated the high ability of ETM in predicting the activity investigated.

A comparison of single photon and dual X-ray absorptiometry of the forearm in children and adults

We compared single photon absorptiometry (SPA) to dual x-ray absorptiometry (DXA) for determination of bone mineral content (BMC), bone mineral density (BMD), and bone width (BW) of the forearm. The SPA and DXA measurements were done on the same subjects, using Lunar densitometers. The measurements were performed over the proximal radius (1/3 shaft) of the nondominant arm in 285 healthy, Caucasian females and males, ages 9-53. Correlation, linear, and split regression analyses for all subjects, and for subgroups (adults and children), were performed to compare SPA and DXA measurements. Corresponding measurements performed on two densitometers were highly correlated: r = 0.987, 0.975, and 0.943 for BMC, BMD, and BW, respectively. The corresponding measurements were also very similar in value, ranging from 0.9% to 4.1% difference, although they were different statistically. Correlations dropped slightly when subjects were separated into adult and children subgroups, and therefore, split regression analysis was performed resulting in R2 (adjusted) values of 97.6%, 95.5%, and 89.0% for BMC, BMD, and BW, respectively. Because the group indicator was statistically significant (p < 0.001) only for the BMC measurements but not for BMD and BW, linear regression of the whole sample was done as well. The difference in fitted values between the two regression methods was insignificant; therefore, we concluded that linear regression was sufficient for description of the relationship between SPA and DXA measurements. The precision study showed that the DXA had better reproducibility than SPA. The DXA precision in vivo (CV%) for BMC, BMD, and BW was 1.06, 0.83, and 0.95, respectively; and the SPA precision for same variables was 2.08, 2.12, and 0.95, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)