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Biomedical subjects

A Bogdan

Publications and source records attributed to A Bogdan.

At least 55 records · Page 3Linked to original sources
PubMed1990

Effect of shift work on the night-time secretory patterns of melatonin, prolactin, cortisol and testosterone.

In a study of the internal desynchronization of circadian rhythms in 12 shift workers, 4 of them, aged 25-34 years, agreed to be sampled every 2 h during their night shift (0000 hours to 0800 hours). They were oil refinery operators with a fast rotating shift system (every 3-4 days). We found marked changes in the secretory profiles of melatonin, prolactin and testosterone. Melatonin had higher peak-values resulting in a four-times higher amplitude than in controls. With respect to prolactin and testosterone, peak and trough times were erratic and the serum concentrations were significantly decreased in shift workers. Serum cortisol presented a decreased rhythm amplitude together with higher concentrations at 0000 hours in shift workers. This study clearly shows that fast rotating shift-work modifies peak or trough values and rhythm amplitudes of melatonin, prolactin, testosterone and cortisol without any apparent phase shift of these hormones. Whether the large rhythm amplitude of melatonin may be considered as a marker of tolerance to shift work, as reported for body temperature and hand grip strength, since it would help the subjects to maintain their internal synchronization, needs further investigation.

Adult↗
PubMed1990

Cortisol and cortisone production in rat and mouse adrenal incubations.

The presence of 17 alpha-hydroxylase in rodent adrenals is debated. The presence in blood of mice of 11-deoxycortisol together with the absence of cortisol is well known. We demonstrated here the in vitro synthesis of 17 alpha-hydroxyprogesterone and cortisol from [3H]progesterone in rat and mouse adrenals. We have shown that these syntheses represented 45 and 28% of those of 11-deoxycorticosterone and corticosterone, respectively, from progesterone. These data clearly suggest the presence of a 17 alpha-hydroxylase activity in vitro in these rodents adrenals. In addition, a noticeable synthesis of cortisol (0.87-1.57% per mg tissue, i.e. 52-64% per incubation flask) from 11-deoxycortisol was also observed and was inhibited by 0.1-0.3 mumol of Metyrapone and SKF 12185. These results allow to underline that the adrenals of rat and mouse, two species commonly used in laboratory experiments, may be used for in vitro investigations on cortisol metabolism from exogenous radioactive precursors.

Adrenal Cortex Hormones↗
PubMed1989

Circadian and seasonal variations of electrolytes in aging humans.

The circadian and seasonal variations of a set of routinely determined variables (chloride, sodium, potassium, calcium, inorganic phosphorus, magnesium, creatinine, urea and urate) were documented in young men (mean age +/- SD: 24.0 +/- 3.9 yr) and in healthy elderly men (75.3 +/- 6.6) and women (78.2 +/- 9.1). The same urinary variables, except magnesium, were studied in young men. The circadian variability of serum variables was between 2 and 11% except for serum inorganic phosphorus (12-22% according to the group). By contrast, urinary chloride, sodium and potassium revealed large peak-trough differences (55-75%) and the variability of urinary creatinine, urate and urea was also not negligible (20-30%). ANOVA validated seasonal variations for most of the plasma variables and for urinary calcium, phosphorus and uric acid. No age or sex difference in either 24 h means or amplitudes could be observed. These data are of interest for the concept of reference values, for the diagnosis of certain bone and renal disease as well as for chronooptimization in treatment of potential electrolytes deficiency states.

Aged↗
PubMed1989

Lack of effect in vivo of clofibrate on adrenal steroid secretion.

Clofibrate inhibits the synthesis of adrenal steroids when administered in vitro. In the present study the effect in vivo of clofibrate on adrenal steroid secretion has been investigated. Basal levels of plasma progesterone, corticosterone, aldosterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, dehydroepiandrosterone sulphate and dehydroepiandrosterone, and their response to ACTH 1 mg im, were not reduced by chronic administration of clofibrate 2 g per day p.o. for 8 to 34 days to 6 hyperlipidaemic men.

17-alpha-Hydroxyprogesterone↗
PubMed1989

Evidence of 11 beta-hydroxylase deficiency in a patient with cortical adrenal adenoma.

We explored a 61 year old woman with mild hirsutism. An adrenal tumor was found in the left adrenal, which was held responsible for the androgen secretion. The in vitro incubation of the tumor tissue showed an impaired 11 beta-hydroxylation of 11-deoxycortisol. This is a rare and unusual case of adrenal pathology showing that a deficiency in 11 beta-hydroxylase activity does not rule out the presence of an adrenocortical adenoma.

Adenoma↗
PubMed1989

Cross-linked DTPA polysaccharides for magnetic resonance imaging. Synthesis and relaxation properties.

An attempt was made to develop a macromolecular paramagnetic contrast agent that would be easily and inexpensively synthesized, low in toxicity, and quickly eliminated from the body after completion of the desired imaging studies. Under more rigorous conditions than attainable with proteins, the bis-anhydride of DTPA was reacted in anhydrous, hot DMSO with dextrans ranging in size from 17,000 molecular weight (MW) to 150,000 MW in various ratios of DTPA to glucose units from 1:1 to 1:40. Up to several hundred DTPA units per saccharide complex could be attached with this technique. Depending on the initial polysaccharide length and ratio of DTPA to glucose units, various degrees of cross-linking occur. Average MW of the polymers ranging from 17,000 to particles several million MW could be synthesized. The ester bond thus formed is stable for prolonged periods in solution. Depending on the polymer size, soluble material, gels, or particles are formed. Relaxation rates of the soluble material are similar or better than Gd-DTPA on a molar basis of Gd3+. The particulate material demonstrates T2 shortening out of proportion to T1, as expected for solid material, from increased susceptibility effects.

Contrast Media↗
PubMed1989

Activity of melatonin and other pineal indoles on the in vitro synthesis of cortisol, cortisone, and adrenal androgens.

The in vitro effects of 13 indole compounds on the synthesis of glucocorticoids and of adrenal androgens in sheep adrenal glands has been studied from 11-deoxycortisol as a precursor. This work demonstrates the activating effect of some indole compounds on 11 beta-hydroxylase and 17,20-desmolase and the inhibitory effect of most of them on 11 beta-hydroxysteroid dehydrogenase. Three categories could be distinguished: 1) compounds without any effect (5-hydroxytryptophan, 5-hydroxytryptamine); 2) compounds moderately increasing (10-30% as compared with controls) cortisol yields (tryptamine, melatonin, 6-hydroxymelatonin, 5-methoxytryptophol, indomethacin); and 3) compounds markedly increasing (80-100%) cortisol yields (5-methoxyindole acetic acid, 5-hydroxyindole acetic acid, 2-methylindole, 5-hydroxytryptophol, N-acetyl-5-hydroxytryptamine). In fact, since most of the studied indoles reduced 11 beta-hydroxysteroid dehydrogenase activity, the actual activation of cortisol synthesis was four to five times less. Lastly, all the studied compounds, but melatonin, increased the activity of 17,20 desmolase as seen from 11 beta-hydroxyandrostenedione and 11-ketoandrostenedione yields. The possible in vivo effects of the indoles for therapeutic use needs further studying.

Adrenal Glands↗
PubMed1988

[Specificity of CA 125 tumor marker. A study of 328 cases of internal medicine].

The sensitivity and specificity of CA 125 were evaluated retrospectively in 328 patients, some of them with several diseases, seen between January, 1985 and December, 1986. High levels of CA 125 were found in 110 assays performed in patients with solid tumour (43 cases), peritoneal, pleural or pericardial effusion (39 cases), infection (34 cases), malignant blood disease (3 cases) and various non-malignant and non-infective diseases (45 cases). High CA 125 levels were most frequently observed in patients with effusion. The frequency of cancer increased with the CA 125 titre. CA 125 levels were particularly high in ovarian, peritoneal and uterine carcinomas. It was higher in ovarian cancer than in other types of cancer and further elevated in the presence of effusion, irrespective of the primary cancer. All patients with ovarian carcinoma had ascites. The sensitivity of CA 125 was 59 per cent and its specificity 74 per cent in solid tumours and malignant blood diseases. The corresponding figures in solid tumours alone were 72 per cent and 75 per cent respectively. While there can be no doubt that CA 125 is valuable in the follow-up of patients with ovarian carcinoma, the clinical context and notably the presence of an effusion must be taken into account when asking for a CA 125 assay to evaluate the cause of an inflammatory syndrome or of an alteration of the general condition, since CA 125 levels may be raised in a wide variety of non-malignant diseases, and especially in effusions and infections. In this study, a CA 125 titre higher than 1,000 U/ml was always due to the presence of cancer; lower titres must be interpreted according to the clinical context and sometimes the course of the disease.

Adolescent↗
PubMed1988

Tumor markers in non-malignant diseases.

This paper reviews the specificity of tumor markers recently introduced in clinical use, namely CA 19-9, CA 125, CA 15-3, CA 50 and SCC antigen. It appears that a large number of either biological conditions (age, sex, pregnancy, menstruation etc.), intoxication (smoking and alcohol addictions) or various non-malignant diseases do affect the serum levels of tumor markers. These data are of practical use in the interpretation of tumor marker determinations in the follow-up of cancer patients.

Antigens, Neoplasm↗
PubMed1988

[Critical study of current tumoral markers].

A number of biological markers have been recently introduced in clinical use as an aid for diagnosis and monitoring of malignant tumors. Some of them are relatively tumor-specific, i.e. CA 125 for non-mucinous ovarian cancer, CA 15.3 for breast cancer, PSA for prostate cancer, CA 19.9 for colo-rectal and pancreatic cancers. The clinical usefulness, the sensitivity and specificity of these tumor markers and of a few others (CA 50, SCC and TPA) are commented in this review.

Antibodies, Monoclonal↗
PubMed1988

Time-dependence of urinary neopterin, a marker of cellular immune activity.

Neopterin, a marker of cellular immune system activation, is produced by human macrophages after induction by interferon gamma (secreted by T-lymphocytes) and is eliminated mostly in urine. We have documented the circadian rhythm of urinary neopterin in five healthy young men (about 25 years old), using voidings collected during 48 h at fixed 4-h intervals. We repeated the experiment three times, one week apart. Neopterin was measured by high-performance liquid chromatography (HPLC). We clearly show a peak of the excretion of neopterin in the early morning (around 0630 hours +/- 2 h), with total variability (peak-trough difference) reaching 51%. Neopterin is commonly assayed in urinary fractions, so it is imperative to use urine specimens collected at the same time of day--e.g., the first morning urines--to avoid misinterpretation in follow-up of patients.

Adult↗
PubMed1987

Prevalence of magnesium and potassium deficiencies in the elderly.

Concentrations of magnesium and potassium in erythrocytes and plasma were determined in a population of 381 unselected elderly men and women, most of them in their eighties. The effects of biological factors (age, sex, weight) and a large set of pathological conditions, malignant or not, were examined. Analyses of variance showed a relation between age and concentrations of plasma potassium and between weight and concentrations of plasma magnesium. The chi-square test showed correlations between low concentrations of plasma magnesium and diabetes, abuse of alcohol and tobacco, and also between low values for erythrocyte magnesium and hypertension. Low values for plasma potassium were correlated with hypertension whereas high values were correlated with cardiovascular disease. Although some of the differences in the mean concentrations observed were statistically significant, these differences were always small. Most interesting was the distribution of the concentrations of the cations. This study shows that assays of both of these cations in erythrocytes were better than assays in plasma to evidence a deficiency. Indeed, about 20% of the studied population had low concentrations of both erythrocyte potassium and magnesium, whereas 2 and 10% had low values for plasma potassium and magnesium, respectively. This study underlines the large prevalence of magnesium and potassium deficiencies in the elderly, an observation we could not attribute to pathology or treatment. Routine electrolyte studies therefore appear to be justified in aged human subjects.

Age Factors↗
PubMed1986

Decreased nocturnal plasma melatonin peak in patients with a functional alteration of the retina in relation with uveitis.

A functional alteration of the retina is present in patients suffering from uveitis. Because of the relation between the pineal gland and the retina we documented possible modifications of melatonin secretion in patients with uveitis. Plasma melatonin was assayed in 19 patients and 16 age-matched controls. Blood samples were drawn at the known high and low points of the circadian rhythm of the hormone, i.e. 02.00 and 11.00 h, respectively. We found that the nocturnal peak of plasma melatonin was greatly decreased (45%) in patients with uveitis. These data cannot be related to the impairment of retinal melatonin synthesis alone. The possibility exists that the decline of the nocturnal peak of melatonin we have reported is due to a pineal inflammation in patients with uveitis, as observed in the experimental autoimmune uveitis induced in rats by retinal S-antigen.

Adolescent↗
PubMed1986

Age-related changes in both circadian and seasonal rhythms of rectal temperature with special reference to senile dementia of Alzheimer type.

The biological rhythms of rectal temperature were documented in young (circadian variations) and elderly (circadian and seasonal variations) human subjects either in apparent good health or suffering from senile dementia of Alzheimer type (SDAT). All the subjects were synchronized. Data obtained showed a decrease of the body core temperature rhythm amplitude in the healthy elderly for each documented season but not in patients with SDAT. Seasonal variations in these rhythms were observed in these elderly groups of persons.

Aged↗
PubMed1986

Differences between young and elderly subjects in seasonal and circadian variations of total plasma proteins and blood volume as reflected by hemoglobin, hematocrit, and erythrocyte counts.

Circadian and seasonal rhythms in total plasma proteins were documented in healthy young men (around 24 years old), and in elderly subjects (both sexes), including senile-dementia patients in their eighties. The concentration of plasma proteins within a given group changed predictably (7-13%), depending on the hour of sampling and the season. Concentrations decreased noticeably around 04:00 h, then peaked around 08:00 h (shortly after waking). The 24-h mean concentrations of total plasma proteins were lower in the elderly groups than in the young men. But the seasonal variations of the 24-h mean values were strikingly larger in the elderly groups (7-8 g/L) than in the young men (2-5 g/L). Moreover, the circadian profiles of plasma proteins differed from the profiles of hematocrit, hemoglobin, and erythrocyte counts. Evidently, circadian variations of blood volume may not be the only element accounting for the variations of plasma protein concentrations. We suggest that the rhythms in plasma protein concentrations be taken into account when reference values are set. Circadian and seasonal variations in plasma proteins may also significantly affect the transport and binding of drugs, especially in the aged.

Adult↗
PubMed1985

o,p'-DDD (mitotane) treatment for Cushing's syndrome: adrenal drug concentration and inhibition in vitro of steroid synthesis.

o,p'-DDD is an inhibitor of adrenal steroid synthesis currently used for therapy of Cushing's syndrome. Conflicting data have been published on the relationship between the plasma level of the drug and its clinical and biological effects. The levels of o,p'-DDD and o,p'-DDE in various tissues obtained from treated patients have been measured and are compared with data on in vitro steroidogenesis in adrenal tissues from the same patients. o,p'-DDD was found in all samples and o,p'-DDE in half of them, both levels being high when the tissue lipid concentration was high. There was considerable variability in lipid content from one tissue to another and within a tissue from one sample to another; only the drug to lipid ratio seems able to provide a reproducible index of drug entry into a tissue. No relationship was found between the tissue concentration of the drug and the total dose administered or inhibition of the steroid biosynthetic step studied.

17-alpha-Hydroxyprogesterone↗