Search PubMed⌕ Search

Biomedical subjects

B Lech

Publications and source records attributed to B Lech.

11 recordsLinked to original sources
PubMed1992

Exogenous melatonin modifies the circadian rhythm but does not increase the level of some immune parameters in the chicken.

The effect of daily injection of the pineal hormone melatonin and naltrexone, an opioid antagonist, on the circadian rhythm and the level of immune parameters (plaque forming cell [PFC] number, serum agglutinin titer, lymphoid gland weight, total white blood cells (WBC) and their fraction number, and serum lysozyme [LZ] content) was examined in White Leghorn cockerels and female BALB/c mice kept in LD 12:12. Animals were immunized ip with sheep red blood cells (SRBC) to stimulate their immune system. Subcutaneous injections of melatonin, naltrexone, or both drugs together were made 2 hr before the end of light, for 4 or 5 days, beginning on the day of immunization. The day following the fifth injection, chickens were sacrificed over a 24 hr period every 4 hr (experiment I) or twice daily, i.e., at the beginning of light and dark phases (experiment II). Mice were killed on the day following the fourth injection at the beginning of light, and splenic PFC number was determined (experiment III). In experiment I, the existence of the diurnal rhythm was evaluated by cosinor analysis. Melatonin injections entrained the circadian rhythm in anti-SRBC serum agglutinins, but it did not influence circadian rhythmicity in other parameters examined. The circadian rhythm in total WBC number and their fractions was entrained by naltrexone treatment. Melatonin injections did not affect either the diurnal mean of parameters examined or the weight of lymphoid organs. Splenic PFC number in chickens was diminished by both melatonin and naltrexone injections, whereas in mice it was increased by melatonin, and naltrexone antagonized that effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination↗
PubMed1979

Assessment of adrenocortical function in asthmatic patients on long-term triamcinolone acetonide treatment.

The adrenocortical function of 48 adult asthmatic patients on long-term corticoid therapy was studied. All were treated with triamcinolone acetonide (TA) for from two to six (average 3.5 years). The adrenocortical function was assessed using a short Synacthen test as a screening procedure and a five-hour Synacthen test for TA exclusively treated patients with abnormal response in the short test. Among patients on long-term TA were nine with abnormally short Synacthen tests. The five-hour test revealed six abnormal responses (12% of the entire group of TA treated patients). Contrary to previously expressed opinions the authors feel that TA long-term treatment only occasionally causes steady adrenal suppression.

Adrenal Cortex Function Tests↗
PubMedDate not supplied

Bronchospasm and rhinitis induced in allergic patients by in vitro released mediators. I. Methodology.

This paper reports the development of an in vitro model of mediator production to be applied to patients with allergic asthma or rhinitis. All the selected patients were atopics and exhibited type I hypersensitivity to Candida alb., D. pter., or both. Heparinized blood was taken. The lymphomonocytes were separated and challenged in vitro with the specific antigen. After two hours of incubation and careful washing, the cells were further cultured for 24 hours and the supernatants removed. Skin tests and bronchial provocation tests were done with supernatants with known concentration of proteins. As a control for cell activation, two lymphokines, i.e. MIF and MF were determined in supernatants. The results demonstrated a dose-related bronchial and nasal response in allergic individuals with specific supernatants. On the other hand they failed to respond to supernatants recovered from non-sensitized cells, cells sensitized with unrelated antigens or sensitized cells obtained from non-allergic individuals. In almost 50% of the cases the immediate bronchial response, which was always present was sustained and persisted for several hours. Active supernatants always induced strong immediate skin responses. In conclusion, this in vitro model of mediator production seems to be valuable for the analysis of the physiopathological mechanism of these diseases.

Animals↗
PubMedDate not supplied

Bronchospasm induced in allergic patients by in vitro released mediators. II. Analysis of possible mechanisms.

In a previous report, it was shown that cultures of peripheral blood leukocytes, from allergic individuals, in the presence of antigen will produce bronchospasm inducing agents in the supernatants. In this study, the responsibility of several mediators was analyzed, i.e., histamine, IgE, prostaglandins E2 and F2 alpha and leukotrienes C4. The results failed to demonstrate a significant release of histamine. Measurable amount of IgE could be recovered from active supernatants. Following removal of IgE and IgE-antigen complexes, the immediate bronchospastic response disappeared without so many changes in the delayed response. PGE2 and PGF2 alpha could be demonstrated in the active supernatants, which could be blocked by indomethacin. No significant differences in the bronchial challenge could be demonstrated between the two samples. Samples contained significant amount of leucotrienes C4. Treatment of cultures with NDGA (cyclooxygenase inhibitor) blocked almost completely the bronchial response. Therefore, in this assay, IgE, IgE-antigen complexes and leukotrienes C4 seem to play a major role in the induction of bronchospasm in sensitized individuals. We are clearly aware that the mediators production in vitro may eventually reflect only part of the events taking place in vivo. Nevertheless, this model allows the analysis of several major mediators and eventually some of their interactions. The role of PAF is now under study.

Asthma↗