AIDS epicenter.
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Acquired Immunodeficiency Syndrome↗
Biomedical subjects
D Mavoungou
Publications and source records attributed to D Mavoungou.
Steroid and gonadotropin hormone levels in young African women with filarial infection.
Serum levels of dehydroepiandrosterone sulfate (DHEAS), testosterone (T), progesterone (P), estradiol (E2), prolactin (PRL), cortisol (F) and gonadotropins (FSH, LH) were analysed by radioimmunoassay for 125 schoolgirls aged 14-16, in a zone of endemic filariasis 3 days after menses. Two groups were identified: the infected group in which 38 subjects had circulating Loa loa and or Mansonella perstans microfilariae as determined by the Knott's concentration technique, and the non-infected group (87 subjects without microfilaremia). All results are expressed as the mean +/- SD. No significant difference was found between the two groups for age (14.47 +/- 1.37 yr vs 14.50 +/- 1.37 yr) or for body wt (46.10 +/- 8.45 kg vs 47.06 +/- 8.26 kg). There was a tendency to lower levels of DHEAS in the infected group by comparison with controls (54.92 +/- 37.34 micrograms/dl vs 66.80 +/- 47.18 micrograms/dl) while in the same infected group more subjects had higher levels of prolactin by comparison with the control group (10.85 +/- 14.16 ng/ml vs 9.80 +/- 5.56 ng/ml). Testosterone, progesterone, estradiol levels and the LH/FSH ratio were lower in the infected group than in the non-infected group (P: 0.25 +/- 0.12 ng/ml vs 0.33 +/- 0.20 ng/ml, P less than 0.025; T: 0.55 +/- 0.17 ng/ml vs 0.62 +/- 0.19 ng/ml, P less than 0.05; E2: 32.95 +/- 19.63 pg/ml vs 66.98 +/- 54.83 pg/ml, P less than 0.001; LH/FSH: 0.91 +/- 0.44 vs 1.30 +/- 0.84, P less than 0.005) respectively. No significant difference was found between the two groups for F; however FSH levels correlated negatively with F levels only in the microfilaremia group (r = -0.38, n = 38, P less than 0.05). Our results suggest that the presence of microfilaremia in our subjects may have contributed to reduced steroid levels, perhaps by involvement of the cyclic AMP kinase system. These observations may explain the delayed menarche and androgen secretion found during puberty in a similar population living in the same zone of endemic filariasis. Microfilaremia should therefore be considered an environmental factor which mediates endocrine disorders in subjects living in tropical filariasis areas.
Adolescent↗
Plasma cortisol and corticosteroid-binding globulin in essential hypertension.
Plasma concentration of cortisol, total CBG-binding capacity, and blood pressure were measured in control subjects (n = 171), patients with essential hypertension (EH; n = 210) and their first-degree normotensive (NR; n = 84) or hypertensive (HR; n = 66) relatives. Mean (+/- SD) plasma cortisol was significantly (p less than 0.001) decreased in EH (10.1 +/- 4.3 g/dl) patients and HR (11.7 +/- 4.1). Plasma cortisol in NR did not differ from control values (14.3 +/- 4.5) but the distribution of individual values covered the entire control-EH (14.6 +/- 5.5) range. Mean (+/- SD) CBG-binding capacity was significantly (p less than 0.001) lower in EH (14.4 +/- 3.0), NR (17.5 +/- 2), HR (17.6 +/- 2.2) as compared to controls (20.9 +/- 2.1), indicating that the decline in EH and in most relatives was mainly in plasma CBG-bound cortisol. The plasma CBG-binding capacity for cortisol was significantly negatively correlated with mean arterial pressure (MAP) in both controls (p less than 0.001) and NR (p less than 0.01) but not in either HR (r = 0.02) or never-treated EH patients. Total afternoon plasma aldosterone was higher (p less than 0.01 vs. controls) in 93 untreated EH patients (11.2 +/- 4.8 ng/dl) than in either 161 first-degree relatives (8.1 +/- 3.4 ng/dl) or 117 controls (7.6 +/- 3.5 ng/dl). The respective aldosterone-binding globulin (ABG) binding capacities for aldosterone were 21.2 +/- 6.7, 20.1 +/- 9.3 and 9.8 +/- 4.0%. In all these subjects taken together, there was a positive correlation between MAP and ABG-binding capacity (r = 51; p less than 0.001). The association of reduced plasma cortisol and decreased CBG binding capacity in EH may be closely related to altered steroid metabolism, which may be partly explained by an abnormality resembling a relative deficiency in adrenal 17 alpha- and 11 beta-hydroxylation. In some EH patients, hypertension may be the result of the ineffectiveness of plasma cortisol in preventing slightly elevated endogenous ACTH levels leading to an increase in ACTH-sensitive steroids.
Adolescent↗
Renin angiotensin aldosterone axis, including aldosterone binding globulin and blood pressure in three species of nonhuman primates.
Variables of renin-angiotensin-aldosterone axis with inclusion of protein binding to specific plasma globulin (ABG), plasma cortisol, and the blood pressure (BP) were measured in 24 chimpanzees, 4 gorillas, and 16 cynomolgus monkeys. ABG activity was readily detected in plasma from the primates. In chimpanzees and gorillas, all the variables under baseline conditions were similar to those in humans. In cynomolgus (Macaca fascicularis), both the ABG binding capacity for aldosterone and the diastolic or systolic BP were significantly higher (p less than 0.001 and p less than 0.01 respectively) than in chimpanzees and gorillas.
Aldosterone↗
Plasma dehydroepiandrosterone, its sulfate, testosterone and FSH during puberty of African children in Gabon.
Plasma levels of dehydroepiandrosterone (DHEA), its sulfate (DHEAS), testosterone (T) and follicle stimulating hormone (FSH) were measured by radioimmunoassay in 111 schoolboys and 95 schoolgirls from 7 to 18 years. 68 male and 55 female adults aged from 19 to 25 were also investigated. Results are expressed as the mean +/- SD, DHEA was the first hormone to vary showing a significant mean increase between the 10 and 11 year age groups of both boys and girls. Higher levels were observed in the age 12 group (boys 164.70 +/- 60.74; girls 256.60 +/- 145.40 ng/dl) but were followed by a significant decrease in both 13 year old groups. Similar increases followed by decreases were also noted for DHEAS, although the increase started between 11 and 12 years and reached a maximum at 13. An abrupt increase in FSH levels between 11 and 12 years followed by a plateau through 15-18 years, was observed for boys and girls. As expected, T levels increasing significantly in boys with the initial rise between 11 and 12 and a climb through to the 15-18 age group. Our results suggest a late plasma DHEAS secretion with adult levels attained after age 19. Menarche was also found to be late.
Adolescent↗
Human salivary or plasma aldosterone- and dehydroepiandrosterone-binding glycoprotein induces hypertension in the rat.
In this study we demonstrated the presence of an aldosterone-binding globulin (ABG) in human saliva. Following ultrafiltration and purification of saliva to electrophoretic homogeneity, this thermolabile globulin called ABG-S appeared to be identical to plasma ABG. It was also shown that both purified ABG-S and plasma ABG bind reversibly, with high affinity (Ka = 1.6 X 10(-9) M, Scatchard plot) to dehydroepiandrosterone sulfate (DHEA-S) to binding sites different from those for aldosterone. Following incubation with human urine both ABG and ABG-S were converted quantitatively into corresponding thermostable forms which appeared to be identical with the human urinary ABG homologue namely ABG-TsU. In addition ABG-S showed the same ability to elevate blood pressure when administered to rats as did ABG-TsU. The fact that an endogenous substance with pressor activity might exist in more than one body fluid suggests further its possible participation in the basic mechanisms of blood pressure regulation.
Animals↗
[Male infertility in Gabon. Comparison of spermatic parameters between fertile and infertile groups].
Aetiology of infertility in Central Africa remains largely controversial. The male factor has been less studied than the female factor. We present data obtained on spermatic parameters in comparison between fertile and infertile groups. Values obtained in fertile men are similar to those observed in European or American countries. Very low values of spermatozoa concentration, percentage of motile and morphologically normal forms were found in infertile male.
Fertility↗
[Malaria: the end of a multimillenia reign?].
Malaria is one of the oldest and more pervasive diseases of mankind with half of the world's population still meeting with Plasmodium. The resistance of the parasite and its carrier, anopheles, at the current levels of antimalaria programs results in recurrence of this illness among the less developed tropical zones. The high risk groups for malaria are pregnant women and children, resulting in a delay of intra-uterine growth, neonatal/infantile morbidity and mortality. Recent progress in molecular biology provide new perspectives for preventive and curative solutions, more specifically in the relationship between host and parasite.
Female↗
Further studies on human plasma aldosterone-binding globulins: isolation, purification, and evidence for heterogeneity.
The present study further characterizes the aldosterone-binding globulin (ABG) in human plasma. Isolations were performed by ultrafiltration, Blue Sepharose CL-6B, or ion-exchange chromatography and gel filtration. New ABG species were identified: interconvertible with ABG in plasma is a thermolabile (MW less than 70,000) and a thermostable ABG macromolecule (MW 27,500). All forms were extensively purified to electrophoretic homogeneity (SDS-PAGE) showing microheterogeneity in isoelectric focusing (pI 4.76 and 4.8) and reversible high-affinity binding for aldosterone. Chromatography of lipoprotein-free plasma in DEAE-Sephadex A-50 gel (ionic gradient) revealed the presence of a dimer of ABG (MW 55,000) which was found to be interconvertible with ABG and was the main carrier of aldosterone in normal fresh plasma. Selective adsorption of albumin from lipoprotein-free plasma on Blue Sepharose CL-6B permitted in a single novel step the complete resolution of bound aldosterone (binding ABG) and bound cortisol (binding corticosteroid-binding globulin). Both ABG and the dimer can be separated from corticosteroid-binding globulin by Blue Sepharose chromatography. A new homeostatic mechanism in which ABG participates in blood pressure regulation by interacting with aldosterone is postulated.
Aldosterone↗
Experimental essential hypertension in the rat?
1. A human urinary thermostable glycoprotein (ABG-TsU) believed to be a homologue of the plasma aldosterone-binding globulin (ABG) was isolated and purified by differential ultrafiltration, ion-exchange chromatography and gel filtration to electrophoretic homogeneity; it showed a charge heterogeneity in electrofocussing. 2. ABG-TsU was administered intraperitoneally to male rats in small daily doses (7 microgram/day per rat). Sustained hypertension developed in 5--8 days. 3. The treated rats showed no changes in plasma electrolytes, aldosterone or plasma renin activity; however, a significant increase in heart weight was observed. 4. This hypertension appears to be adrenal dependent since it is prevented by bilateral adrenalectomy or administration of an aldosterone antagonist, but not by adrenalectomy when aldosterone is given concomitantly with ABG-TsU.
Animals↗
Genetic aspects of plasma aldosterone binding globulins in families of patients with essential hypertension, including isolation of novel thermostable homologues from plasma and urine.
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Adolescent↗
Aldosterone-binding globulin-induced hypertension in the rat. A new experimental model.
A thermostable urinary homologue of the plasma aldosterone-binding globulin (ABG), designated ABG-TsU, was isolated and purified by differential ultrafiltration, ion exchange chromatography, and gel filtration to electrophoretic homogeneity. Scatchard plot analysis using highly purified ABG-TsU demonstrated reversible high-affinity low-capacity binding at separate sites for aldosterone and dehydroepiandrosterone sulfate (DHEA-SO4). ABG-TsU injected intraperitoneally (i.p.) in male rats resulted in sustained hypertension after 5 to 8 days, characterized after 12 days by no changes in plasma Na+ K+, aldosterone, or plasma renin activity (PRA). No histological changes could be detected in the kidneys, brains, or hearts, nor evidence of adrenocortical hyperplasia. This hypertension appears to be aldosterone-dependent since it is prevented by bilateral adrenalectomy or administration of a spironolactone, but not by adrenalectomy when aldosterone is given concomitantly with ABG-TsU. Hemodynamic characterization of this hypertension was carried out in rats after treatment with ABG-TsU or saline i.p. for 14 days. Cardiac output (CO) was measured using the reference sample microsphere method. ABG-TsU-treated rats had significantly higher mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), and CO, while no difference in total peripheral resistance (TPR) was detected. This new animal model of borderline essential hypertension (EH) induced by ABG-TsU, which has a reversible high-affinity binding for aldosterone, results in adrenal-dependent hypertension due at this early phase to an increase in CO without any change in TPR, which remains inappropriately normal.
Adrenalectomy↗
[Manganese impregnation in miners of the Ogooue Mining Company at Moanda (Gabon)].
Analyses on manganese noxiousness have been carried out various working stations of Moanda. The men who are most exposed work in the grinding and packing posts. In the occupational surroundings we have rates of 146.42 mg/m3 of manganese while in the blood the values turn around 2.310 micrograms/l.
Humans↗