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T J James

Publications and source records attributed to T J James.

10 recordsLinked to original sources
PubMed1998

Nicotine-induced norepinephrine release in the rat amygdala and hippocampus is mediated through brainstem nicotinic cholinergic receptors.

Previous studies have shown that nicotine stimulates norepinephrine (NE) release in the rat hypothalamic paraventricular nucleus, which in turn activates the hypothalamo-pituitary-adrenal axis. In the present study, nicotine induced NE release in the amygdala (AMYG) and the hippocampus (HP) of the same rat in vivo. Nicotine (0.065-0.135 mg/kg i.v. at a rate of 0.09 mg/kg/60 sec) dose-dependently increased NE release at both sites with similar potencies. To determine whether the site of action of nicotine is in the brainstem, which contains the noradrenergic cell bodies projecting to AMYG and HP, nicotinic cholinergic receptor (NAchR) antagonists were injected into the cerebral aqueduct before i.v. nicotine. Use of the following antagonists enabled partial characterization of the NAchRs mediating NE secretion: mecamylamine (Mec), dihydro-beta-erythroidine (DH beta E), methyllycaconitine (MLA) and alpha-bungarotoxin (alpha-BTX). Mec inhibited 80% of NE release in AMYG and 87% in HP (IC50 = 6 nmol for both regions). DH beta E blocked 62% of NE release in AMYG (IC50 = 8 nmol) and 63% in HP (IC50 = 15 nmol). Similar to DH beta E, MLA inhibited 60% of NE release in AMYG and 66% in HP (IC50 = 5 nmol for both regions). In contrast, alpha-BTX had no effect on NE release in either region. These results indicate that brainstem NAchRs accessible from the fourth ventricle mediate nicotine-stimulated NE secretion in AMYG and HP. Taken together with prior investigations showing the brainstem expression of mRNAs encoding NAchR subtypes and the selectivity of antagonists for NAchR subtypes, the present studies suggest that brainstem alpha-3 subunits may be involved.

Amygdala↗
PubMed1996

Enzymatic determination of sodium and chloride in sweat.

OBJECTIVE: To develop methods based on enzyme activation for the analysis of sweat sodium and chloride using beta-galactosidase and alpha-amylase, respectively. METHODS: Both were monitored kinetically on the Cobas Fara centrifugal analyzer. The sweat, collected with the Macroduct system, was diluted no more than five-fold for the volumes obtained of 16 to 80 mu L, median 32.5 mu L. The sodium assay utilized a sodium-binding cryptand to maximize linearity. RESULTS: Between-run coefficients of variation (%) at 10, 20, and 50 mmol/L were 3.6, 4.5, and 1.3 for sodium and 7.1, 6.1, and 6.0 for chloride, respectively. The sodium method showed excellent agreement with flame photometry (y = 0.997x + 0.742; r = 0.998), and chloride with a mercuric thiocyanate method (y = 0.995x + 0.485; r = 0.996), giving equivalent discrimination between patients with and without cystic fibrosis. CONCLUSIONS: The methods enable the rapid analysis on the same analyzer of both sodium and chloride in a single dilution of sweat collections of low volume.

Bridged Bicyclo Compounds, Heterocyclic↗
PubMed1995

Regional and lobular variation in neuronal lipofuscinosis in rat cerebellum: influence of age and protein malnourishment.

Various factors other than ageing influence lipofuscinosis in neurons and other cells. Protein malnutrition is one such factor that has been studied. In the present study 3 months old rats were subjected to protein malnutrition (PM) for 3, 6 and 12 months by feeding them with low protein diet (4% protein). An age matched control group of rats was also maintained on a normal diet with high protein content (20% protein). The cerebella from the PM and control group rats were processed for histochemical, biochemical and fluorescent microscopic studies. Quantitative analysis of lipofuscin revealed that PM caused an increase in lipofuscin accumulation in the Purkinje neurons. A similar study on the Purkinje neurons of rats belonging to various age groups i.e. 6, 9 and 15 months, showed an increase in lipofuscin accumulation with age. Further, the increase in lipofuscinosis in ageing and PM rats was found to be varying. The maximum lipofuscin accumulation with PM was in the neurons of the 5th and 7th (75% and 71%, respectively) lobule of vermian region. The maximum increase in lipofuscin accumulation with age was found to be in lobule III (105.8%) of vermian region. Such a variation occurred in the hemisphere region also. Moreover, taking the two regions of cerebellum as a whole, neurons of the hemisphere region accumulated more amount of lipofuscin than those of the vermis region. The authors feel that the regional specificity of lipofuscin accumulation is to be studied in terms of the functional role of the various regions of a particular tissue in question.

Age Factors↗
PubMed1995

Lipofuscin accumulation in neurons with restraint stress.

Stress induced lipofuscinosis was studied in rat cerebellum. 3 month old wistar rats were subjected to restraint stress by keeping them immobile for 24, 48 and 72 hours duration. This was achieved in specially prepared cages which allowed no space for the rats to move; giving a stress to the animal. The cerebella from the stressed groups rats were removed after the experiment and were processed for fluorescent microscopical, histochemical and fluorimetric study of lipofuscin. The lipofuscin content in the Purkinje neurons was compared with that of the control rats which were of the same age, size and weight as of the experimental rats. The results showed that the lipofuscin content in the neurons of the experimental rats was more than that of the control ones. In gist, while 24 hrs. stress caused a 28.9% increase in lipofuscin content, 48 hrs. stress resulted in a 38.3% increase. This shows that restraint stress can be a good experimental model for lipofuscinogenesis and ageing studies.

Aging↗
PubMed1994

The in vivo and in vitro effects of antibodies against rabbit beta 2-integrins.

Beta 2-integrins play a crucial role in the development of an inflammatory response. In ours study, Abs have been used to investigate the role of individual members of this family of adhesion molecules in both in vivo and in vitro assays. An Ab against rabbit LFA-1 effectively inhibited the adhesion of rabbit polymorphonuclear leukocytes to rabbit endothelial cells in culture and was also effective in blocking cell recruitment to the peritoneum and vascular leakage at dermal sites of inflammation. An Ab that inhibited rabbit complement receptor type 3 function in vitro failed to inhibit cell recruitment to the peritoneum or vascular leakage in response to intradermal FMLP. Histologic studies suggested that the anti-complement receptor type 3 Ab may have modified the cell migration process.

Animals↗
PubMed1993

An adaptable computer interface for radioimmunoassay.

To assist data handling of results derived from radioimmunoassay the RIACalc Multigamma counter package was interfaced to a laboratory information system. The interface was bidirectional and allowed transfer of worklists and results. A suite of programs was written for the laboratory information system that enabled flexible data processing to meet a range of laboratory requirements. One utility within the suite contained a simple user definable rule based routine for automatically requesting additional tests. Use of the interface and new software improved laboratory efficiency and illustrated the potential benefits of decision making systems.

Clinical Laboratory Information Systems↗
PubMed1992

'Dark' cell formation under protein malnutrition: process of conversion and concept of 'semi-dark' type Purkinje cells.

This paper deals with some deleterious effects of protein malnourishment in rat cerebellum. Severe protein deprivation enhanced the formation of 'dark' cells in white rats. It is postulated that abnormal changes in the neuronal contents induced by nutritional stress play a vital role in the formation of the 'dark' cells through an intermediary stage, 'semi-dark' cells. Centrophenoxine a lipofuscinolytic agent, however, seems to interfere with the process of formation of 'dark' cells and/or helps reconversion of the 'dark' cells into the normal or 'light' type Purkinje cells.

Animals↗