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Biomedical subjects

Y Touitou

Publications and source records attributed to Y Touitou.

At least 109 records · Page 6Linked to original sources
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

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↗
PubMed1989

Urinary neopterin in pulmonary sarcoidosis. Relationship to clinical and biologic assessment of the disease.

Neopterin is a metabolite of guanosine-triphosphate, released in vitro by macrophages under the control of gamma-interferon and described as a marker of T cell activation in vivo. We have compared the urinary neopterin/creatinine ratio (mumol/mol) in patients with pulmonary sarcoidosis (n = 66), interstitial lung diseases other than sarcoidosis (nonsarcoid ILD, n = 35), and 45 normal control subjects. For the sarcoid population as a whole, urinary neopterin was higher (496 +/- 52 mumol/mol [mean +/- SEM]) than in control subjects (126 +/- 5 mumol/mol) (p less than 0.001). In patients with nonsarcoid ILD, urinary neopterin was frequently higher in granulomatous and/or lymphoproliferative diseases (hypersensitivity pneumonitis, tuberculosis, primitive Sjögren's syndrome, and malignant lymphomas) (781 +/- 193 mumol/mol, n = 10) but remained normal in other types of nonsarcoid ILD [( 163 +/- 14 mumol/mol, n = 25]: histiocytosis X, idiopathic pulmonary fibrosis, lung collagen-vascular diseases, diffuse neoplasms, pneumoconiosis; p less than 0.001 compared with sarcoidosis). We have also evaluated the relationship between urinary neopterin and the clinical or biologic markers currently used to assess sarcoidosis: alveolar lymphocytosis in lavage fluid (ALY), 67-gallium scan semiquantitative index (67Ga), or serum angiotensin-converting enzyme (SACE). Sarcoid patients with the highest urinary neopterin were those in whom mean values of these markers were the highest (p less than 0.05, all comparisons). Patients with positive markers (i.e., either clinical expression of sarcoidosis-ALY greater than 30%-67Ga greater than 20-SACE greater than 60 U/ml) had significantly higher urinary neopterin levels than did other sarcoid patients (p less than 0.05, all comparisons).

Adult↗
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

[Hormonal regulation and metabolic inter-relations of magnesium].

Magnesium ion is of great importance in physiology by its intervention in 300 enzymatic systems, its role in membrane structure and its function in neuromuscular excitability. The skeleton is the first pool of magnesium in the body. Intestinal absorption, renal metabolism, bone accretion and resorption of magnesium are very similar to those of calcium. Magnesium metabolism is accurately controlled, in particular by parathyroid hormone, 25 - dihydroxy vitamin D3, calcitonin, catecholamine and estrogens. The main regulation mechanisms of magnesium metabolism are located in the kidney which is the principal excretory organ.

Calcitonin↗
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

Seasonal modulation of the circadian time structure of circulating T and natural killer lymphocyte subsets from healthy subjects.

A seasonal modulation of the circadian time structure of circulating T and natural killer (NK) lymphocyte subtypes was documented in five healthy men aged 24-36 yr. Venous blood was obtained every 4 h for 24 h from each subject in January, March, June, August, and November 1984. Three subjects were also studied in April and/or August and/or November 1983 for the T subsets only. Mononuclear cells were isolated on Ficoll-Paque gradient and aliquots were incubated with OKT3, OKT4, OKT8, or HNK-1 monoclonal antibodies for characterizing all, T, T helper, T suppressor-cytotoxic, and NK lymphocytes, respectively, under an epifluorescence microscope. An effect of both sampling time and study month was statistically validated (P less than 0.01) with both two-way analysis of variance and cosinor for the peripheral counts in total, pan-T, T helper, and NK lymphocytes (cells per cubic millimeter). Seasonal changes affected both the circadian patterns and the 24-h mean values. Thus the double amplitude (total extent of variation) of the circadian rhythm in circulating total, T and T helper lymphocytes varied between 0 in March (P greater than 0.30; no rhythm) and up to 46-68% of the 24-h-mean (M) in November, with acrophases (times of maximum, 0) localized in the first half of the night (P less than 0.001). Maximal values were found at 8:30 h for both T suppressor-cytotoxic and NK lymphocytes; a smaller second peak was also found at 20:30 h, and a 12-h rhythm was validated by cosinor (P less than 0.0001), with no patient change in waveform along the year scale. A circannual rhythm was statistically validated by cosinor for total (0 in November), pan-T (0 in March), T suppressor-cytotoxic (0 in December), and NK lymphocytes (0 in October). A rhythm with a period equal to 6 mo was found for circulating T helper cells with 0 occurring both in April and October. Seasonal variations in the incidence of several immunologically related diseases may correspond to an endogenous circannual time structure.

Adult↗
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

Circadian rhythms in circulating T lymphocyte subtypes and plasma testosterone, total and free cortisol in five healthy men.

Circadian variations of circulating T lymphocyte subtypes and their possible relations with those of endogenous cortisol or testosterone were investigated in five healthy young men. Venous blood (40 ml) was obtained every 4 h for 24 h from each subject in January, March, June, August and November. Leucocyte and differential counts were measured. Mononuclear cells were isolated on Ficoll-Paque gradient, and samples were incubated with OKT3, OKT4 or OKT8 monoclonal antibodies for characterizing all T, T helper and T suppressor-cytotoxic lymphocytes respectively. The proportion of labelled lymphocytes was determined under an epifluorescence microscope and the counts of circulating lymphocyte subsets (cells/mm3) computed. Total and free cortisol and testosterone were also determined in the corresponding plasma samples. Results from analysis of variance and cosinor indicated statistically significant differences (P less than 0.001) as a function of both individual subject and circadian sampling time for all variables. Circadian rhythms (with a period, tau = 24 h) were validated for total, T and T helper lymphocytes and for the T helper: T suppressor-cytotoxic ratio (P less than 0.001), with double amplitudes (2A, total extent of variation accounted for by the fitted cosine function) ranging from 25% up to 50% of the 24 h mean (M), and acrophases (phi, time of maximum) localized near 0100 h. A rhythm with tau = 12 h characterized circulating T suppressor-cytotoxic lymphocytes (P less than 0.001; 2A = 36% of M; phi = 0830 and 2030 h). Circadian rhythms were also found for plasma cortisol (either total or free) and testosterone (P less than 0.001). No correlation was found however between time-qualified data of these hormones and the immunological variables herein investigated (162 pairs of data) whether or not a 4 h or an 8 h lag time was considered to allow for hormonal actions to operate. This suggests that neither the circadian organization of the adrenal cortex nor that of the testis play a prominent role in the circadian time structure of the circulation of T lymphocytes.

Adult↗
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

Early rising or delayed bedtime: which is better for a short night's sleep?

The present study compares the effects on sleep and the subsequent period of wakefulness of delaying bedtime of 2 h or advancing rising time by 2 h in subjects clearly differentiated by morningness or eveningness in their circadian rhythms. Twelve young healthy good sleepers, six morning types (MT) and six evening types (ET), were selected. The data obtained from the second 24 h (night and day) with delayed bedtime (DB) and advanced rising time (AR) were compared with those obtained in the reference condition (R) with normal sleep schedules. Sleep was recorded polygraphically and rectal temperature was continuously monitored during the nights and during the day following the second night of each condition. Subjective estimations of alertness, performance tasks and urinary steroids were analysed. Early rising appeared to be more disturbing than a late bedtime. The second shortened night showed fewer characteristics of recovery sleep in AR than in DB. The decrease in self rated alertness was a function both of the type of condition (DB or AR) and of the morning-evening typology of the subject. The largest decrease was observed in AR and in the ET subjects. AR also resulted in the most pronounced decrease in performance tasks and in an increase in urinary 17 ketosteroids without changes in the 17 hydroxy-corticosteroids. The effects on rectal temperature were limited to short periods after bedtime in DB and rising time in AR.

17-Hydroxycorticosteroids↗