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Biomedical subjects

S Bem

Publications and source records attributed to S Bem.

At least 19 recordsLinked to original sources
PubMed2001

Effect of tartaric acid on conformation and stability of human prostatic phosphatase: an infrared spectroscopic and calorimetric study.

The solution structure and thermal stability of human prostatic acid phosphatase (hPAP) in the absence and in the presence of tartaric acid were studied by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The temperature dependence of the infrared spectrum and DSC scans indicate that hPAP undergoes thermal unfolding at a temperature between 49.5 and 52.5 degrees C. Binding of tartaric acid does not lead to major changes in the secondary structure of hPAP, however, hPAP with bound tartaric acid shows a significantly increased thermal stability. These results helped to better understand the mechanism of hPAP unfolding at the elevated temperature.

Acid Phosphatase↗
PubMed2000

Use of hyperbaric oxygen chamber in the management of radiation-related complications of the anorectal region: report of two cases and review of the literature.

PURPOSE: This article was undertaken to present two cases of nonhealing ulcers that occurred after primary radiation therapy and local excision of suspected residual or recurrent anal carcinomas. Both patients responded favorably to hyperbaric chamber treatment. Review of the literature is discussed, including cause, clinical presentation, diagnosis, and options for management of radiation-related complications in the anorectal region and use of hyperbaric oxygen treatment in colorectal surgery. METHODS: The cases of two patients with recurrent or residual anal carcinomas were reviewed. Objective clinical, laboratory test, and intraoperative findings were implemented to define this pathologic entity precisely, results of its treatment, and management of radiation-related complications. RESULTS: The study shows clinical effectiveness of hyperbaric chamber treatment for nonhealing wounds in the previously radiated anorectal region. The refractory wounds of both our patients healed. The patients were rendered free of symptoms. CONCLUSIONS: Substantial pathologic changes in the irradiated tissues leading occasionally to nonhealing radiation proctitis are relatively infrequent consequences of radiation therapy for pelvic malignancies. Excisional and incisional biopsies of the radiation-injured tissues result in chronic ulcers accompanied by debilitating symptoms. Hyperbaric chamber treatment seemed to be a very effective means of therapy of radiation proctitis and nonhealing wounds in the involved anorectal region after conventional therapy had failed.

Anus Diseases↗
PubMed1998

Immunological effects of occupational exposure to metallic mercury in the population of T-cells and NK-cells.

This paper presents a study of the counts of lymphocytes, (CD3+)T-cells, (CD4+)T-helper and (CD8+)T-suppressor and (CD16+)NK-cells in the peripheral blood of 101 males with a history of occupational exposure to metallic mercury vapours (Hg0) and in 36 males without this exposure. These workers were divided depending on the duration of exposure: 37 males with a short-term history of exposure to Hg0 (up to 10 years) and 64 males with a history of long-term exposure (10 to 37 years). For the determination of T-cell populations monoclonal antibodies were used in indirect immunofluorescence tests. The time weighted average of mercury concentrations in air was 0.028 mg m-3. Mercury concentration in the urine of the exposed subjects ranged from 20-260 micrograms dm-3, and in blood it was from 4 to 72 micrograms dm-3. Stimulation of the T-cell line was noted as evidenced by increased numbers of (CD3+)T-cells, (CD4+)T-helper and (CD8+)T-suppressor cells in the workers with < 10 or > 10 years' exposure to Hg0. Lower increase count of (CD3+)T-cells and (CD4+)T-helper cells than (CD8+)T-suppressor cells was the cause of decreased values in the (CD3+)T/(CD8+)T-suppressor ratio and (CD4+)T-helper/(CD8+)T-suppressor ratio in the workers with < 10 or > 10 years' of exposure. Moreover, no changes were observed in the T-cell populations between workers with < 10 and those with > 10 years' exposure. In addition, statistical analysis of the effects of age and duration of exposure to Hg0 on the studied immunological parameters indicates that exposure duration may affect some of the values. These quantitative changes of T-cell population as well as changes of the (CD3+)T/(CD8+)T-suppressor and (CD4+)T-helper/(CD8+)T-suppressor ratio have been proposed as immunological indicators of exposure to Hg0, which can be used for monitoring and to explain the origin of autoimmunity disorders induced by metallic mercury.

Adult↗
PubMed1998

[Usefulness of determining urinary markers of early renal damage for monitoring nephrotoxicity during occupational exposure to mercury vapors].

Using nephelometry, concentration of albumin, IgG, transferrin, retinol binding protein (RBP) alpha 1-microglobulin were determined in urine of 83 males with history of occupational exposure to metallic mercury vapours from 0.6 to 37 years, and in 30 non-exposed males. The weighted average of mercury air concentrations was 0.028 mg/m3. Duration of occupational exposure to mercury vapours did not elevate urine excretion of proteins. The urine concentration of proteins in question were higher (especially beta 2-m) in workers with urine mercury concentration between 51 and 150 microliter-1 and highest in workers with urine mercury concentrations above 150 micrograms l-1 and the differences were significant. In addition, a positive correlations between urine mercury concentrations and alpha 1-m (r = 0.33) as well as between urine mercury concentration and albumin (r = 0.31) were observed. In conclusion, the determination of proteins in urine as markers of early renal damage may be useful for monitoring occupational exposure to mercury vapours, especially in the group of workers with elevated values of urine mercury concentrations.

Adult↗
PubMed1998

[The effects of occupational exposure to nitrogen dioxide (NO2) on the immunological parameters in workers].

The study of T-cell subpopulation: T CD3+, T CD4+, T CD8+; NK CD16+ and B CD19+ cells as well as of serum concentrations of immunoglobulins G, A, M, E, complement components C3c and C4, total circulating immune complexes (CIC), CRP, haptoglobin, ceruloplasmin and transferin, was carried out in 16 males, smokers and non-smokers. The control group of smokers and non-smokers comprised 36 males not exposed to any chemical compound. The study was performed also in two groups of non-smokers: 5 workers occupationally exposed and 7 non-exposed controls. For the determination of T-cells, NK- and B CD19+ cells populations monoclonal antibodies were used in indirect immunofluorescence tests. Passive sampling spectrophotometric method was employed to determine NO2 and NO concentrations in the work environment air. Their mean values were 0.0867 +/- 0,0585 mg x m-3 (from 0.0165 to 0.1960) and 0.0614 +/- 0.0263 mg x m-3 (from 0.0220 to 0.1090), respectively. The number of total leucocytes and lymphocytes in the group of 16 smokers and non-smokers exposed to NO2 and NO was increased. Stimulation T-cells line in the men exposed to NO2 and NO was evidenced by an increased number of T CD3+ cells, about two-fold increase in absolute number of T CD4+ cells (p < 0.001), an increased number of T CD8+ cells (p < 0.001) and by an enhanced value (by 24.7%) of the T CD4+/T CD8+ ratio. In the group of 16 persons exposed to NO2 and NO serum IgG concentration was elevated (p < 0.01), C3c C4 decreased (p < 0.001), and serum CIC enhanced by about two times (p < 0.001). Stimulation T-cells line in the groups of 5 non-smoking workers exposed to NO2 and NO was evidenced by an increased number of T CD3+ (p < 0.05), T CD4+ (p < 0.05) and T CD8+ cells but without any change in the value of the T CD4+/T CD8+ ratio. In addition, decreased serum C3c and C4 levels together with serum CIC elevated by 76.7% (p < 0.05) were evidenced in this group on non-smokers. Moreover, significant positive correlations between NO2 concentrations in the air and the numbers of total lymphocytes, T CD3+, TCD4+, T CD8+ cells or IgG: (magnitude of r in the range between 0.31 and 0.71), as well as significant negative correlations between NO2 concentrations in the air and C3c (r = 0.44) in the group of 16 smoking and non-smoking workers were calculated. In this group significant positive correlation between NO concentrations in the air of the workplace and counts of T CD3+, T CD8+, B CD19+ (magnitude of r in the range between 0.51 and 0.63), haptoglobin and ceruloplasmin (magnitude of r from 0.37 to 0.58), as well as significant negative correlation between NO concentrations in the air and serum levels of IgG, IgA and IgM (magnitude of r from -0.67 to -0.47) and CIC (magnitude of r = -0.39) were also observed. In the group of 5 exposed non-smoking workers, the values of correlation coefficients magnitude of r between NO2 and NO concentrations in the work environment air and immunological parameters were similar to those in the whole group. The results obtained suggest that during occupational exposure NO2 may play a more important role mainly in the process of inflammation but exogenous NO seems to act as modulating factor of this proinflammatory NO2 effect through a greater and exposure-dependent influence mainly on B CD19+ cells and other parameters of humoral immunity.

Adult↗
PubMed1997

Successive Approximations to an Adequate Model of Attention

Everybody knows the phenomena summarized with the term attention: concentration, focalization, limitation, selection, and intensification (see, e.g., James, 1890/1950). The explanation of these phenomena is, however, a different matter. Problems easily arise with regard to what has to be explained and with regard to the style of explanation. A problem of the first kind is the "methodology of 'bad focus'": the explanation starts with and is fixated on an intuitively striking but nonessential behavioral feature or cognitive achievement. A problem of the second kind is a "virtus dormitiva" explanation: the explanation starts with emphasizing one aspect of the observed phenomena, the emphasized aspect receives an interesting and suggestive name, and that name with its connotations is used as a concept in the explanation. At the start of contemporary, behavior-based, information processing psychology, a virtus dormitiva explanation infiltrated the functional accounts of the phenomena of attention; the empirical observation that people show performance limitations was translated into the theoretical concept of a communication channel with a limited capacity. That limited capacity notion became the core concept in what can be called the standard theory of attention. This standard theory of attention faced severe difficulties in explaining the guidance of attention by the information processor's goals and intentions. Subsequent modifications, concerned with removing these difficulties, revealed that selection, guided by goals and intentions, is the essential behavioral feature and that the observed performance limitations are a result of this selection. So, the limited capacity theorizing was not only plagued by a virtus dormitiva explanation, it also suffered from the methodology of bad focus.

Journal Article↗
PubMed1996

Effects of occupational exposure to mercury vapors on T-cell and NK-cell populations.

The counts of lymphocytes, (CD3+) T-cells, (CD4+) T-helper and (CD 8+) T-suppressor and (CD 16+) NK-cells were determined in the peripheral blood of 81 males with a history of occupational exposure to metallic mercury vapors and in 36 males without this exposure. For the determination of T-cell populations monoclonal antibodies were used in indirect immunofluorescence tests. The weighted mean of mercury concentrations in air was 0.028 mg x m-3. Mercury concentration in the urine of the exposed subjects ranged from 10-240 micrograms x l-1, and in blood it was from 4-30 micrograms x l-1. Stimulation of the T-cell line was noted as evidenced by increased number of T-cells by 35% in the workers with exposure to mercury vapors below or by 38% in the workers over 10-years, by increased number of T-helper cells by 42% (p < 0.001) in the workers with exposure below or by 60% (p < 0.001) in the workers over 10 years and by increased number of T-suppressor cells by 85% (p < 0.001) in the workers below or by 96% (p < 0.001) in the workers over 10 years exposure. Lower increase of T-helper cells population than T-suppressor cells population was the cause of decreased value of the T-helper/T-suppressor ratio by about 21% (p < 0.01) in the workers with exposure below and over 10 years. No changes were observed in the T-cell populations between workers with up to 10 and those with over 10 years exposure. The quantitative changes of T-helper cells and T-helper/T-suppressor ratio may represent an immunological indicator of exposure to mercury vapors. Presented changes in human T-lymphocytes population associated with occupational exposure to mercury vapors have been proposed to explain the origin of more frequent autoimmunity induced by mercury.

Adult↗
PubMed1995

Lymphocytes, T and NK cells, in men occupationally exposed to mercury vapours.

Lymphocytes, T-cells (CD3+), T-helper (CD4+) and T-suppressor (CD8+) as well as NK-cells (CD16+) counts were determined in the peripheral blood of 81 males occupationally exposed to metallic mercury vapours and of 36 non-exposed males using monoclonal antibodies in indirect immunofluorescence tests. Mean weighted mercury concentration in air accounted for 0.0028 mg x m-3. Urine mercury concentrations ranged from 0 to 240 micrograms x 1(-1) and concentrations in the blood varied from 0 to 30 micrograms x 1(-1). Stimulation of T-lymphocytes manifested by an increased number of T-cells, T-helper and T-suppressor was observed. Quantitative change in T-cells night be an immunological index of exposure to mercury vapours as indicated by a positive correlation between the exposure duration and the number of these cells.

Adult↗
PubMed1991

Parameters of immunity acute phase reaction in men in relation to exposure duration to mercury vapours.

The study was carried out in 89 men aged 21 to 57 years with a history of exposure to mercury vapour from 2 to 26 years during occupational work involving chlorine production by the method of mercury electrolysis. The workers were divided into three groups depending on the duration of occupational exposure: 1) 32 workers with a short history of exposure 2-10 years, 2) 37 workers with medium-long exposure - 11-20 years, and 3) 20 workers with a history of long exposure - 21-26 years. The urinary concentrations of mercury in these individuals was 73 +/- 60 microliters x 1(-1), and in blood this concentration was not exceeding 50 microliters x 1(-1). The control group comprised 40 men aged 17 to 52 years. They had not had any occupational exposure to chemicals, or harmful physical factors. On the basis of clinical, haematological and biochemical studies 89 workers with occupational exposure to mercury vapour were regarded as clinically healthy. None of them had any symptoms and signs of the complete neurasthenic syndrome or organic brain injury. Increased nervous excitability was the complaint of 24 workers, 9 had headaches, sleep disturbances were reported by 5, and a feeling of tiredness and apathy was mentioned by 5 men. EEG recording demonstrated 81 normal tracings, and moderately pathological records in 8 men. The parameters of immunity and proteins acute phase reaction were determined, measuring the concentration of immunoglobulins, lysozyme, C3c, C4, alpha 1-acid glycoprotein, haptoglobin and ceruloplasmin in serum. A lower level of IgA, IgG and lysozyme was only noted in individuals with occupational exposure exceeding 20 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Proteins↗
PubMed1990

[Indicators of immunity and acute phase reaction in men in relation to the duration of exposure to mercury vapors].

The indices of immunity and acute phase reaction in 89 men exposed for 2 to 26 years to mercury vapours were assessed on the basis of immunoglobins, lysozyme, C3c, C4, alpha 1-acid glycoproteins, haptoglobin and ceruloplasmin concentrations in blood serum. Urinary mercury concentration amounted to 73 +/- 60 micrograms x l-1 whereas in blood it did not exceed 50 micrograms x l-1. A decrease in concentration of IgA, IgG and lysozyme in persons who worked for over 20 years was found. The observed phenomenon did not affect the anti-infection and antitumor immunity of the workers.

Acute-Phase Reaction↗
PubMed1989

[Changes in acid hydrolase activity in white blood cells as an indicator of occupational exposure to mercury vapors].

Using histochemical methods the activity was determined of acid phosphatase and beta-glucuronidase in 89 men exposed to mercury vapours during chloride production by means of mercury electrolysis. The activity of both enzymes was low and the intensity of the histochemical reactions was correlated with duration of exposure and mercury concentrations in urine and blood. The determination of the activity of acid hydrolases may be used for monitoring of the biological consequences of occupational exposure to mercury vapours.

Acid Phosphatase↗
PubMed1989

[Enzyme deficiencies in leukocytes of workers exposed to mercury vapors. I. Neutrophils].

The influence of occupational environment intoxicated by mercury on the enzymatic reactivity of neutrophils has been determined by investigating the activity of 10 enzymes in the peripheral blood neutrophils. The study comprised 89 men who have worked from 2 to 26 years producing chlorine by mercury electrolise method. The concentration of mercury in blood and urine of 15 +/- 13 micrograms l-1 and 44 +/- 43 micrograms x g creatinine-1, respectively was found. The deficiency of 1 enzyme was stated in 33%, of 2 enzymes in 27%, of 3 enzymes in 13% and of 4 enzymes in 3% of the workers exposed. The normal enzymatic reactivity of neutrophils was found in 25% of them.

Adult↗
PubMed1985

Carprofen and the therapy of gastroduodenal ulcerations by ranitidine.

The effects of the addition of carprofen (Roche), a new nonsteroidal antiinflammatory agent, to regular 4-5 week ranitidine (300 mg/day) therapy on gastric secretion, serum gastrin level and ulcer healing, have been examined in 15 gastric ulcer (GU) and 60 duodenal ulcer (DU) patients. Carprofen at a therapeutic dose (300 mg/day) was well tolerated by both GU and DU patients and did not give rise to any major adverse effects. In an open trial on 15 GU (all receiving carprofen), complete endoscopic ulcer healing was found in 9 patients after 3 weeks and in 6 others after 5 weeks of treatment. In a double blind, placebo controlled trial on 60 DU (30 receiving carprofen and 30 receiving placebo), complete ulcer healing was seen after 2 weeks in 23 on carprofen and 22 on placebo, and after 4 weeks in all tested patients. Pentagastrin-induced maximal acid secretion examined 24 h after the last dose of treatment was significantly reduced in DU, but not in GU, patients, and was accompanied by a significant rise in plasma gastrin levels. No change in gastric histology was observed in any patient tested. This study provides evidence that carprofen added to antiulcer ranitidine therapy shows excellent gastrointestinal tolerance, and does not interfere with ulcer healing; it is, therefore, recommended in the treatment of arthritic patients with peptic ulcer disease.

Adult↗