Biomedical subjects

A Dragomir

Publications and source records attributed to A Dragomir.

10 recordsLinked to original sources

PubMed2000

X-ray microanalysis of intestinal chloride transport in vitro and in vivo.

Chloride secretion from crypt cells in mouse duodenum or jejunum was investigated in in vivo and in vitro models by electron probe X-ray microanalysis. IBMX-induced chloride secretion could not be demonstrated in vivo, presumably because of competing systemic effects. However, chloride secretion could be induced by 300 microM IBMX in vitro. The best results were obtained under the following conditions: a long preincubation of the tissue slices in high potassium or saline buffer (preferably in high potassium buffer), oxygenated with 95% O(2) and 5% CO(2), at low temperature (4 degrees C), followed by IBMX stimulation in saline buffer at 37 degrees C. Chloride efflux was accompanied by efflux of Na and K.

1-Methyl-3-isobutylxanthine↗

PubMed2000

Effects of nicotine on intestinal epithelial cells in vivo and in vitro: an X-ray microanalytical study.

It has been suggested that nicotine may have a beneficial effect on ulcerative colitis. Little is known, however, about the mechanism of such an effect. In the present study, the effects of nicotine on intestinal ion transport were investigated by X-ray microanalysis. In addition to an in vivo study, an in vitro system was established by pre-incubating pieces of small intestine in solutions of different ionic composition, in an attempt to stabilize the intracellular ionic composition. It was observed that nicotine caused a loss of Cl (indicative of net chloride efflux) in the villous epithelial cells and the cells of Brunner's glands, in vitro both in Na+ and in K+-containing medium. In in vivo experiments, exposure of mice for 10 days to nicotine in drinking water resulted in a lowering of the cellular chloride concentration in villous epithelial cells of the small intestine, cells of Brunner's glands and epithelial cells of the colon. The results may indicate a disturbance of fluid transport in the intestine by nicotine. Possible mechanisms, such as inhibition of uptake of chloride across the basolateral membrane, are discussed.

Animals↗

PubMed1999

Antidepressant effect of ingested nicotine in female rats of Flinders resistant and sensitive lines.

Both major depression and depressive symptoms are associated with a high rate of nicotine dependence, and a history of major depression has an adverse impact on smoking cessation. The main objective of this study was to investigate whether continuous ingestion of nicotine affects indices of depressive behavior in the rat. We compared cholinergic- and serotonergic-hypersensitive Flinders Sensitive Line rats (FSL), a genetic animal model of depression, with their control counterparts, Flinders Resistant Line rats (FRL). Female rats of both lines were allowed access to a solution of nicotine bitartrate (100 microg/mL) in tap water for 14 days. Subsequent behavioral testing revealed striking effects of continuous ingestion of nicotine on depressive-like behavior of both lines. FSL and FRL rats that ingested nicotine for 14 days displayed less immobility in the 10-min forced-swim test (an index of depressive-like behavior) relative to the animals of both lines that were not exposed to nicotine or exposed to nicotine for shorter periods of time. This finding indicates that ingested nicotine has antidepressant properties that are independent of the genetic difference between FSL and FRL female rats. Animal studies on nicotine ingestion and withdrawal may become an important source of insights into the comorbidity of depression and nicotine self-administration.

Animals↗

PubMed1998

Genetically transmitted cholinergic hyperresponsiveness predisposes to experimental asthma.

The excitatory innervation of the airway smooth muscle is primarily cholinergic in nature. However, the potential neural mechanism(s) underlying airway hyperresponsiveness, one of the hallmarks of asthma, is not fully understood. In this study, cholinergic hyperresponsive Flinders sensitive line (FSL) rats and their control counterparts, Flinders resistant line (FRL) rats, were repeatedly challenged with different doses of nebulized methacholine (0, 4, 16, 64, and 256 mg/ml) for 5 min. Airway responsiveness was assessed in spontaneously breathing, unrestrained animals by means of whole body plethysmography. Increased airway responsiveness of FSL rats was evidenced as a more pronounced increase in Penh value (enhanced pause, an index of bronchoconstriction) across different concentrations of methacholine. In subsequent experiments, FSL and FRL rats were sensitized to ovalbumin and challenged with nebulized antigen. Our results indicate that the genetically transmitted cholinergic hyperresponsiveness of the FSL rat is paralleled by an increased susceptibility to allergen-induced bronchoconstriction and inflammation of the airways. This study provides further evidence that neural factors can play an important role in determining airway responsiveness and thus may be relevant for the expression of asthma. In addition, the FSL rat may be a useful model for studies of airway hyperresponsiveness.

Airway Obstruction↗

PubMed1998

Storage of trachea for X-ray microanalytical studies of tracheal submucosal glands.

Pig trachea is a good model system to study airway fluid transport with relevance to human diseases such as cystic fibrosis, since both in pig and in man, the submucosal glands play a quantitatively important role in fluid secretion. Pig trachea can be easily obtained from the local slaughterhouse. In the present study, we investigated the procedure to transport the tissue from the slaughterhouse to the laboratory where physiological experiments can be carried out. Transport of the tissue in a solution with high K+ content (resembling the intracellular environment) maintained the morphology of the glands and a high intracellular K/Na ratio. Physiological experiments can be carried out in solutions with a high Na+ concentration resembling the extracellular environment. The glands secrete chloride on stimulation with alpha-adrenergic, beta-adrenergic, cholinergic and peptidergic agonists. Transport and temporary storage of tissue in high K+ solutions expands the scope of possible X-ray microanalytical studies in the field of pathophysiology.

Animals↗

PubMed1997

Knee pain and knee osteoarthritis severity in self-reported task specific disability: the Johnston County Osteoarthritis Project.

OBJECTIVE: To evaluate the contributions of radiographic knee osteoarthritis (OA) and knee pain severity to self-reported disability performing upper and lower extremity tasks in a rural, population based sample. METHODS: Data from 1192 African-American and Caucasian participants in the Johnston County Osteoarthritis Project were analyzed with multiple logistic regression to examine the roles of Kellgren-Lawrence radiographic knee OA grade and knee pain severity in self-reported difficulty performing 20 activities of the Health Assessment Questionnaire. Potential confounders included age, sex, race, marital status, education, and body mass index. RESULTS: Forty-three percent reported difficulty performing at least one task. Mild knee pain was independently associated with difficulty performing 16 upper and lower extremity tasks, and moderate/severe knee pain with all 20 tasks, with little change after adjustment (p < 0.0001). In contrast, mild radiographic knee OA was associated with difficulty in only 4 mobility and transfer tasks: climbing 5 steps, taking a tub bath, getting in/out of a car, and performing chores. Moderate/severe radiographic knee OA was associated with difficulty in 17 of 20 tasks (in 10 of 17, p < 0.0001), except lifting a cup, opening car doors, and turning faucets. However, no associations between radiographic knee OA and difficulty were statistically significant after adjustment for knee pain and the above factors. CONCLUSION: Knee pain severity was the strongest risk factor for self-reported difficulty performing tasks of upper and lower extremity function. Future studies of disability should include data on knee pain severity.

Activities of Daily Living↗

PubMed1996

Self-reported functional status in osteoarthritis of the knee in a rural southern community: the role of sociodemographic factors, obesity, and knee pain.

OBJECTIVE: This study examined the roles of sociodemographic factors (age, race, gender, education, marital status), obesity, and severity of radiographic knee osteoarthritis (OA) and knee pain on self-reported functional status. METHODS: The sample included 1,272 African-American and Caucasian individuals, aged 45 years or older, from the Johnston County Osteoarthritis Project. Analysis of variance was used to assess variation in mean Health Assessment Questionnaire (HAQ) scores by the above variables. RESULTS: Mean HAQ scores differed by severity of radiographic knee OA and knee pain, obesity, and all demographic factors (P < 0.0001), except race. Only age, female sex, obesity, and knee pain severity were independent effects (P < 0.0009). Disability associated with knee pain varied by both radiographic knee OA severity and obesity. CONCLUSIONS: Knee pain severity was more important than radiographic knee OA severity in determining disability. Obesity was independently associated with disability and compounded disability from knee pain. Studies of disability in knee OA should include assessment of obesity, severity of radiographic knee OA, and severity of knee pain, as well as their interactions.

Activities of Daily Living↗

PubMed1996

Ethnic differences in self-reported functional status in the rural south: the Johnston County Osteoarthritis Project.

OBJECTIVE: We examined ethnic differences in self-reported functional status in a rural, population-based sample in North Carolina. METHODS: Data from 1,197 African-American and Caucasian participants, aged 45 and older, in the Johnston County Osteoarthritis Project were analyzed using multiple logistic regression to examine differences in difficulty performing tasks of the Health Assessment Questionnaire (HAQ) and in risk factor profiles associated with difficulty. RESULTS: Forty-three percent reported difficulty in one or more HAQ tasks. African-Americans were more likely than Caucasians to report difficulty performing 3 tasks (P < 0.04); these differences were minimal after adjustment for confounders. For some tasks, risk factor profiles included body mass index in African-Americans only, and age and female gender more often in Caucasians. Low educational attainment was part of the risk factor profile for walking in African-Americans. CONCLUSIONS: Differences in proportions of African-Americans and Caucasians reporting difficulty in performance of HAQ tasks were minimal, but risk factor profiles for difficulty appeared to vary by ethnicity.

Activities of Daily Living↗

PubMed1992

Selective immunosuppression by administration of major histocompatibility complex (MHC) class II-binding peptides. I. Evidence for in vivo MHC blockade preventing T cell activation.

Draining lymph node cells (LNC) from mice immunized with hen egg white lysozyme (HEL) display at their surface antigen-MHC complexes able to stimulate, in the absence of any further antigen addition, HEL peptide-specific, class II-restricted T cell hybridomas. Chloroquine addition to these LNC cultures fails to inhibit antigen presentation, indicating that antigenic complexes of class II molecules and HEL peptides are formed in vivo. MHC class II restriction of antigen presentation by LNC from HEL-primed mice was verified by the use of anti-class II monoclonal antibodies. Coinjection of HEL and the I-Ak-binding peptide HEL 112-129 in mice of H-2k haplotype inhibits the ability of LNC to stimulate I-Ak-restricted, HEL 46-61-specific T cell hybridomas. Similar results are obtained in mice coinjected with the HEL peptides 46-61 and 112-129. Inhibition of T hybridoma activation can also be observed using as antigen-presenting cells irradiated, T cell-depleted LNC from mice coinjected with HEL 46-61 and HEL 112-129, ruling out the possible role of either specific or nonspecific suppressor T cells. Inhibition of T cell proliferation is associated with MHC-specific inhibition of antigen presentation and with occupancy by the competitor of class II binding sites, as measured by activation of peptide-specific T cell hybridomas. These results demonstrate that administration of MHC class II binding peptide competitors selectively inhibits antigen presentation to class II-restricted T cells, indicating competitive blockade of class II molecules in vivo.

Amino Acid Sequence↗

PubMedDate not supplied

[Pseudophakic uveitis].

One of the most important complication in the cataract surgery is the uveitis of the IOL ("toxic lens syndrome"). There are shown the main factors related to the artificial lens, viscoelastic materials and sutures, which may provoke inflammatory reactions. The symptoms may appear early after the operation or later. Concerning those things there is presented a study achieved in the University Clinic of Ophthalmology of the Central Military Hospital.

Adolescent↗