Involvement of supraspinal imidazoline receptors and descending monoaminergic pathways in tizanidine-induced inhibition of rat spinal reflexes

The neuronal pathways involved in the muscle relaxant effect of tizanidine were examined by measurement of spinal reflexes in rats. Tizanidine (i.v. and intra-4th ventricular injection) decreased the mono- and disynaptic (the fastest polysynaptic) reflexes (MSR and DSR, respectively) in non-spinalized rats. Depletion of central noradrenaline by 6-hydroxydopamine abolished the depressant effect of tizanidine on the MSR almost completely and attenuated the effect on the DSR. Co-depletion of serotonin by 5,6-dihydroxytryptamine and noradrenaline resulted in more prominent attenuation of tizanidine-induced inhibition of the DSR. Supraspinal receptors were then studied using yohimbine- and some imidazoline-receptor ligands containing an imidazoline moiety. Idazoxan (I1, I2, I3, and alpha2), efaroxan (I1, I3, and alpha2), and RX821002 (I3 and alpha2), but not yohimbine, an alpha2-adrenergic receptor antagonist with no affinity for I receptors, antagonized the inhibitory effects of tizanidine. Thus, supraspinal I receptors (most likely I3) and descending monoaminergic influences are necessary for tizanidine-induced inhibition of spinal segmental reflexes.     

Real Time-PCR HBV-DNA Analysis: Significance and First Experience in Armed Forces

Background

HBV DNA quantitation is used extensively world wide for the diagnosis and monitoring of treatment of Hepatitis B virus (HBV) infection. However, it has still to be popular in India. The aim of this study was to quantitate HBV – DNA by Real time – PCR method in Hepatitis B and in immuno-compromised patients, to compare the results with HBeAg detection and to monitor the response to therapy of chronic Hepatitis B patients to antivirals.

Methods

Ninety one serum samples of Hepatitis group of patients (all HBsAg positive), 41 samples from immuno-compromised patients (all HBsAg negative) and 49 patients of Chronic Hepatitis B group (all HBsAg positive) were the subjects of this first ever study in Armed Forces. Twenty serum samples from healthy volunteers and non-hepatitis B patients served as negative controls. The amplification detection was carried out in a Rotor-Gene 2000-sequence detector

Results

Amongst Hepatitis B group, 33% (30/91) of the samples were positive for HBV-DNA and 26% (24/91) of samples were positive for HBeAg. In the immuno-compromised group of patients 14.6% (6/11) of samples were positive for HIV-DNA and 9.7% (4/41) were positive for HBeAg. Of the Chronic Hepatitis B patients on treatment, all (100%) were positive by HBV-DNA, whereas 29/49 (59.2%) were positive by HBeAg before treatment. After treatment with antivirals, 06/49 (12.2%) were positive by both tests and 11/49 (22.5%) were positive only by HBV-DNA. 32/49 (65.3%) patients became negative serologically after therapy.

Conclusion

HBeAg status did not necessarily reflect HBV-DNA level in the serum, as 10/91 (11%) in the Hepatitis B group, 2/41 (4.9%) in the immuno compromised group and 20/49 (40.8%) patients in the Chronic Hepatitis B group were positive for HBV-DNA but negative for HBeAg. HBV-DNA was not found to be positive amongst any of the negative controls. Real time – PCR is a sensitive and reproducible assay for HBV-DNA quantitation and may be started in Armed Forces referral centers in the near future.Key Words: Real time – PCR, Chronic Hepatitis B, HBV – DNA, Antivirals     

Relationship between oral sensory thresholds and depressive moods

AIMS: The aims were to compare the sensory thresholds on the tip of the tongue with on the dorsum of the hand, and to investigate the relationship between the sensory threshold and depressive mood with volunteers whose psychological conditions were normal. METHODS: Fifty-five subjects (28 women, 27 men) took psychiatric structured diagnostic interview and Self-rating Depression Scale (SDS). In the next step, the quantitative sensory tests (light touch sensation and thermal sensory test) were carried out on the tongue and the hand. Then we investigated the relationship between depressive moods and sensory thresholds on the tongue and the hand using logistic regression model. RESULT: The sensory thresholds on the tip of the tongues were significantly different from those on the dorsum of the hands. Only on tongue tip, increment of SDS had relation to the thresholds of innoxious thermal stimulation (OR=0.152, 95% CI. 0.049-0.478) and noxious heat stimulation (OR=0.352, 95% CI. 0.169-0.734). CONCLUSION: This finding might support for the idea that depressive mood had closer association with the tongue of the orofacial areas than the dorsum of the hand.     

Accuracy and precision of a system for assessing severity of tooth wear

PURPOSE: The purpose of this study was to introduce a computer-assisted quantitative tooth wear-analyzing system and test its accuracy and precision. MATERIALS AND METHODS: An image of a horizontally projected dental arch was captured, and the facet area of each tooth was calculated using a digital image analyzer. For normalization, the facet area of the individual tooth was divided by the total area of the corresponding tooth; this result was the tooth wear score. The accuracy and precision of this method were determined through the intraclass correlation coefficient using 10 dental casts. Tooth wear on the dental casts of 50 subjects was actually measured. RESULTS: The accuracy of the tooth wear score determined by a newly trained examiner was greater than 0.85 of the intraclass correlation coefficient; this was tested against the score determined by consensus of three experienced examiners. The reproducibility within a 1-week interval was also greater than 0.85. With regard to the tooth wear score from 50 sets of dental casts, the distribution of tooth wear was generally consistent with data reported in the literature. CONCLUSION: The results suggest that the newly trained examiner can exhibit adequate accuracy and precision after appropriate training in identifying tooth wear facets. Recorded data from 50 subjects added face validity to this new system.     

Diabetes mellitus decreases hippocampal release of neurotransmitters: an in vivo microdialysis study of awake, freely moving rats

Possible diabetes mellitus-induced changes in hippocampal monoaminergic activities were studied to understand the relationships between neurotransmitter levels and various abnormalities in freely moving diabetic rats. We used both experimentally (STZ rats) and spontaneously diabetic rats (WBN/Kob rats) as the diabetic animal model, and compared the findings with those obtained from non-diabetic rats (C rats). Measurement of neurotransmitters (serotonin and dopamine) was carried out using an in vivo microdialysis method. We found that: 1) the basal level of serotonin in the hippocampus was lowest in WBN rats, followed by STZ rats, then by C rats. The level of serotonin in WBN rats was about a half of that in C rats; 2) the basal level of dopamine was also significantly lower in the diabetic WBN and STZ rats than in C rats. The data show that diabetes mellitus decreases in the monoamine release from the hippocampus in both experimentally and spontaneously diabetic rats.     

Establishment of an analyzing method for a Japanese encephalitis virus neutralization test in Vero cells

We established a 50% plaque reduction analyzing method of neutralizing antibody for human serum to Japanese encephalitis virus (JEV) in Vero cells, called the '3 points least-squares regression method' (3LSRM). Our method shows a high correlation with the chick embryo cell method (the current standard method for human serum), using the chart method established by the National Institute of Infectious Diseases of Japan, which is an equation made with retrospective data obtained with the 50% plaque reduction method as a standard measurement method for neutralizing antibody titers to JEV. Our new method is much simpler and more reliable than the current method in that it uses an established cell line, Vero cells, and its results are computed by the 3LSRM.