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T J James

Publications and source records attributed to T J James.

17 recordsLinked to original sources
PubMed2002

Dark neurons in the ageing cerebellum: their mode of formation and effect of Maharishi Amrit Kalash.

Dark neurons are considered a manifestation of neuronal injury and although they cover various grades of damage their mode of formation is not yet clear. Age-dependent alterations in a dark purkinje neuronal population of guinea pigs (10 months and 32 months old) and rats (3 months, 6 months, 12 months, 15 months and 28 months) were studied. Light microscopical and electron microscopical observations revealed a significant increase (P < 0.05) in the number of dark purkinje neurons with age in both the guinea pigs and rats. Extraction of lipids from the cerebellum sections before processing for histochemical reaction resulted in a reduction of the dark neuronal population. In an other set of experiments, significant age-dependent increase in the cathepsin-D activity and lipid peroxidation was documented in the guinea pig cerebellum. Treatment of guinea pigs with Maharishi Amrit Kalash (MAK) (500 mg/kg body wt/day, for two months) significantly inhibited (P < 0.05) the activity of cathepsin-D and lipid peroxidation, and decreased the number of dark neurons. These findings suggest that the number of dark neurons increases with age and MAK prevents the conversion of light to dark purkinje neurons due to its inhibitory effects on cathepsin-D activity and antioxidant properties. We suggest that the conformational changes in the normal protein structure due to higher proteolytic activity and peroxidation of lipid in the aging cerebellum endangers a redundant capability for various staining agents and the Osimic acid molecules to react with proteins, lipids and other molecules, leading to an intensified cyto- and karyoplasms electron density.

Aging↗
PubMed2002

Clinical usefulness of cystatin C for the estimation of glomerular filtration rate in type 1 diabetes: reproducibility and accuracy compared with standard measures and iohexol clearance.

OBJECTIVE-Assessment and follow-up of early renal dysfunction is important in diabetic nephropathy. Plasma creatinine is insensitive for a glomerular filtration rate (GFR) >50 ml/min and creatinine clearance is unwieldy and subject to collection inaccuracies. We aimed to assess the reproducibility, reliability, and accuracy of plasma cystatin C as a measure of GFR ranging from normal to moderate impairment due to type 1 diabetes in the presence of a normal plasma creatinine concentration. RESEARCH DESIGN AND METHODS-A sensitive immunoturbidimetric cystatin C assay was examined in 29 subjects with type 1 diabetes and 11 nondiabetic subjects. Duplicate measurements of the following were collected from each subject, 2 weeks apart: cystatin C, enzymatic plasma creatinine, 24-h creatinine clearance, GFR estimated from plasma creatinine by the Cockcroft-Gault equation, and iohexol clearance as a gold standard. RESULTS-Iohexol clearance ranged from 35 to 132 ml. min(-1). 1.73 m(-2). Plasma cystatin C compared well with the other clinically used tests. The reliability of cystatin C, as assessed by the discriminant ratio, was superior to creatinine clearance (3.4 vs. 1.5, P < 0.001) and the correlation of cystatin C with iohexol clearance (Rs -0.80) was similar to that of creatinine clearance (Rs -0.74) and superior to that of plasma creatinine and the Cockcroft-Gault estimate (Rs -0.54 and 0.66, respectively). Duplicate estimations were used to provide an unbiased equation to convert plasma cystatin C to GFR. CONCLUSIONS-Based on this study, cystatin C is a more reliable measure of GFR than creatinine clearance, is more highly correlated with iohexol clearance than plasma creatinine, and is worthy of further investigation as a clinical measure of GFR in type 1 diabetes.

Adult↗
PubMed2001

Improved immunoturbidimetric assay for cystatin C.

An immunoturbidimetric assay for cystatin C was optimized with respect to assay imprecision. After investigating the optimum pH, polyethylene glycol concentration and specimen volume, two modifications were introduced: an increase in specimen volume to 25 microL; and an extension of the pre-incubation period to 240 s. These modifications produced an assay with between-batch imprecision (coefficient of variation, n = 10 or 11) ranging from 3-9% at 0.72 mg/L to 1.3% at 5.29 mg/L. The assay was susceptible to interference from lipaemia and haemolysis but not bilirubinaemia in both the original and modified protocol. Extending the pre-incubation to 240 s improved tolerance to common interferences and retained assay applicability in the routine clinical setting.

Acid-Base Equilibrium↗
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↗
PubMedDate not supplied

Simple biochemical markers to assess chronic wounds.

We investigated the potential for the biochemical analysis of chronic wound fluid to predict healing using simple and widely available analytes in an out-patient clinic setting. Wound fluid was collected from 12 patients attending a leg ulcer clinic and analyzed for a variety of analytes, including lactate, total protein, and albumin. Twelve weeks after collection the wound was assessed for healing (defined as complete healing or greater than 50% reduction in wound size). The median total protein (44.3 +/- 8.8 g/l) and albumin (25.0 +/- 2.3 g/l) concentrations in exudate collected from four healing wounds were significantly higher (p < 0.05) than in exudate from eight nonhealing wounds (median total protein 29.7 +/- 7.6 g/l, median albumin 17.0 +/- 4.3 g/l). No significant difference was observed for lactate. A second specimen of wound fluid was collected from four of the patients (three nonhealing and one healing). The protein analysis confirmed the pattern observed for the first collection: nonhealing wounds had total protein and albumin which remained low compared to healing wounds. No wound with an exudate albumin of less than 20 g/l healed. Both total protein and albumin are stable analytes which can be easily measured in any laboratory and may offer a simple biomarker of healing in chronic wounds.

Aged↗